Apply the distributive property to factor out the greatest common factor. 40f+30 =

Answer:

option a

Step-by-step explanation:

give person above brainliest :)

Answer:

(i) 0.32          (ii) 0.85

(iii) 0.3412    (iv) 0.20

(v) 0.29         (vi) 0.12

Step-by-step explanation:

The data provided is as follows:

   Race                    Smoker (S)         Nonsmoker (N)             Row Total

 White(W)                    290                       560                           850

  Black(B)                     30                        120                           150

Column Total                320                       680                        1,000

(i)

Compute the value of P (S) as follows:

[tex]P(S)=\frac{n(S)}{N}=\frac{320}{1000}=0.32[/tex]

P (S) = 0.32.

(ii)

Compute the value of P (W) as follows:

[tex]P(W)=\frac{n(W)}{T}=\frac{850}{1000}=0.85[/tex]

P (W) = 0.85.

(iii)

Compute the value of P (S|W) as follows:

[tex]P(S|W)=\frac{n(S\cap W)}{n(W)}=\frac{290}{850}=0.3412[/tex]

P (S|W) = 0.3412.

(iv)

Compute the value of P (S|B) as follows:

[tex]P(S|B)=\frac{n(S\cap B)}{n(B)}=\frac{30}{150}=0.20[/tex]

P (S|W) = 0.20.

(v)

Compute the value of P (S∩W) as follows:

[tex]P(S\cap W)=\frac{n(S\cap W)}{T}=\frac{290}{1000}=0.29[/tex]

P (S∩W) = 0.29.

(vi)

Compute the value of P (N∩B) as follows:

[tex]P(N\cap B)=\frac{n(N\cap B)}{T}=\frac{120}{1000}=0.12[/tex]

P (S∩W) = 0.12.

Answer:

We conclude that prenatal cocaine exposure is associated with lower scores of four-year-old children on the test of object assembly.

Step-by-step explanation:

We are given that the 190 children born to cocaine users had a mean of 7.3 and a standard deviation of 3.0 The 186 children not exposed to cocaine had a mean score of 8.2 with a standard deviation of 3.0.

Let [tex]\mu_1[/tex] = population mean score for children born to cocaine users.

[tex]\mu_2[/tex] = population mean score for children not exposed to cocaine.

So, Null Hypothesis, : = 490      {means that the prenatal cocaine exposure is not associated with lower scores of four-year-old children on the test of object assembly}

Alternate Hypothesis, : 490     {means that the prenatal cocaine exposure is associated with lower scores of four-year-old children on the test of object assembly}

The test statistics that will be used here is Two-sample t-test statistics because we don't know about population standard deviations;

                               T.S.  =  [tex]\frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p \times \sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }[/tex]  ~ [tex]t__n_1_+_n_2_-_2[/tex]

where, [tex]\bar X_1[/tex] = sample mean score of children born to cocaine users = 7.3

[tex]\bar X_2[/tex] = sample mean score of children not exposed to cocaine = 8.2

[tex]s_1[/tex] = sample standard deviation for children born to cocaine users = 3

[tex]s_2[/tex] = sample standard deviation for children not exposed to cocaine = 3

[tex]n_1[/tex] = sample of children born to cocaine users = 190

[tex]n_2[/tex] = sample of children not exposed to cocaine = 186

Also, [tex]s_p=\sqrt{\frac{(n_1-1)\times s_1^{2}+(n_2-1)\times s_2^{2} }{n_1+n_2-2} }[/tex]  = [tex]\sqrt{\frac{(190-1)\times 3^{2}+(186-1)\times 3^{2} }{190+186-2} }[/tex] = 3

So, the test statistics =   ~

                                     =  -2.908

The value of t-test statistics is -2.908.

Now, at a 0.05 level of significance, the t table gives a critical value of -1.645 at 374 degrees of freedom for the left-tailed test.

Since the value of our test statistics is less than the critical value of t as -2.908 < -1.645, so we have sufficient evidence to reject our null hypothesis as the test statistics will fall in the rejection region.

Therefore, we conclude that prenatal cocaine exposure is associated with lower scores of four-year-old children on the test of object assembly.

In the null hypothesis, a test always forecasts no effect, while the alternate theory states the research expectation impact, and calculation as follows:

Calculating the pooled estimator of [tex]\sigma^2[/tex], denoted by [tex]S^2_p[/tex], is defined by

[tex]\to \bold{S^2_p= \frac{(n_1 - 1) S^2_1+ (n_2 - 1)S^2_2}{n_1 + n_2 - 2}}[/tex]

Null hypothesis:

[tex]\to H_0 : \mu_1 - \mu_2 = \Delta_0\\[/tex]

Test statistic:

[tex]\to T_0=\frac{\bar{X_1}- \bar{X_2} -\Delta_0}{S_p \sqrt{\frac{1}{n_1}+\frac{1}{n_2}}} \\\\[/tex]

Alternative Hypothesis:

[tex]H_1 : \mu_1 -\mu_2 \neq \Delta_0\\\\ H_1 : \mu_1 -\mu_2 > \Delta_0\\\\H_1 : \mu_1 -\mu_2 < \Delta_0\\\\[/tex]

Rejection Criterion

[tex]t_0 > t_{\frac{\alpha}{2} , n_1+n_2 -2}\ \ \ or\ \ \ t_0 < - t_{\frac{\alpha}{2} , n_1+n_2 -2} \\\\t_o > t_{\alpha , n_1+n_2 -2} \\\\t_o > -t_{\alpha , n_1+n_2 -2}[/tex]

Given value:

[tex]\to S_p=9\\\\\to \Delta_0=0\\\\\to t_0=-\frac{0.9}{3(\sqrt{(\frac{1}{190}+\frac{1}{186})})}=-2.9\\\\\to t_{0.05,374}=1.645\\\\[/tex]

here

[tex]\to t_0 < -t_{0.05,374}[/tex]

hence rejecting the [tex]H_0[/tex]

Since there should be enough evidence that prenatal cocaine exposure is linked to inferior item assembly scores in 4-year-olds.

Find out more about the alternative hypothesis here:

brainly.com/question/18831983

Answer:

x = 38.7

Step-by-step explanation:

Since this is a right triangle, we can use trig functions

tan theta = opp / adj

tan x = 8/10

taking the inverse tan of each side

x = tan ^-1 (8/10)

x=38.65980825

To the nearest tenth

x = 38.7

Answer:

34

Step-by-step explanation:

= 26 + 8

= 34

Answer:

  (3ab)/(2(b-a))

Step-by-step explanation:

The n-th term of an arithmetic progression is ...

  an = a1 +d(n -1)

Then the value of n is ...

  n = (an -a1)/d +1

The sum of an arithmetic progression is the product of the number of terms and the average of the first and last terms. In this sequence, the common difference d is ...

  d = (b -a)

So, the sum is ...

  Sn = (a +2a)/2·((2a -a)/(b -a) +1)

  Sn = (3ab)/(2(b-a)) . . . . sum of the arithmetic progression

__

Example:

The sequence 1, 1.5, 2 has ...

  a = 1, b = 1.5

Its sum is given by the above formula as ...

  Sn = 3(1)(1.5)/(2(1.5 -1)) = 4.5/(2(.5)) = 4.5 = 1 + 1.5 + 2 . . . . yes

Answer:

If a number is an integer, then it is irrational.  ⇒ false statement

Step-by-step explanation:

Let's check:

If a number is an integer, then it is irrational.

- incorrect, as all integers are rational

If a number is a natural number, then it is rational.

- correct, natural numbers are subset of rational numbers

If a number is a fraction, then it is rational.

- correct, they can be shown as p/q

If a number is a whole number, then it is rational.

- correct, whole numbers are subset of rational numbers

The statement "If a number is an integer, then it is irrational" is false.

The statement "If a number is an integer, then it is irrational" is false. This is because not all integers are irrational.

The other statements are all true:

"If a number is a natural number, then it is rational." This is true because all natural numbers are integers, and all integers are rational.

"If a number is a fraction, then it is rational." This is true because a fraction is a number of the form p/q, where p and q are integers and q is not equal to 0. Any number of this form is rational.

"If a number is a whole number, then it is rational." This is true because all whole numbers are integers, and all integers are rational.

Therefore, the false statement is the first one: "If a number is an integer, then it is irrational."

Below is a table summarizing the statements:

Statement                                                                  Truth value    

If a number is an integer, then it is irrational               False

If a number is a natural number, then it is rational     True

If a number is a fraction, then it is rational                  True

If a number is a whole number, then it is rational      True

Learn more about rational numbers on:

brainly.com/question/22221295

#SPJ6

Answer: 139/7

Step-by-step explanation:

Answer:

139/7

Step-by-step explanation:

182/10 = 18.2 < 18 7/11

219/12 = 18 + 3/12 = 18 1/4  < 18 7/11

139/7 = 19 + 4/7 > 18 7/11

179/10 = 17.9 < 18 7/11

Answer:

Step-by-step explanation:

(1-CotA)² + (tanA-1)² = 4csc2A(csc2A-1)

To prove this equation we will take the expression given in left hand side and will convert it into the expression given in right hand side of the equation.

L.H.S. = (1-CotA)² + (tanA-1)²

          = 1 + Cot²A - 2CotA + 1 + tan²A - 2tanA

          = cosec²A - 2CotA + Sec²A - 2tanA

[Since, (1 + Cot²A = cosec²A) and (1 + tan²A = Sec²A)]

          = (cosec²A + Sec²A) - 2(CotA + tanA)

          = [tex](\frac{1}{\text{SinA}})^{2}+(\frac{1}{CosA} )^{2}-2\text{(tanA}+\frac{1}{\text{tanA}})}[/tex]

          = [tex]\frac{1}{(\text{SinA.CosA})^2}-2(\frac{tan^2A+1}{tanA} )[/tex]

          = [tex]\frac{4}{\text{(Sin2A})^{2}}-4(\frac{1}{\text{Sin2A}} )[/tex]

[Since 2SinA.CosA = Sin2A and [tex]\frac{2(\text{tanA})}{1+\text{tan}^{2}A}=\text{Sin2A}[/tex]]

          = 4Cosec²2A - 4Cosec2A

          = 4Cosec2A(Cosec2A - 1)

          = R.H.S. (Right hand side)

Hence the equation is proved.

Answer: 72576m7

Step-by-step explanation:

2m x 8m x 6m x 9m x 7m x 6m x 2m

All together equals my answer 72576m7

Hope this helps!

Answer:

Y=2(1)+4

Y=2+4

Y=6

Step-by-step explanation:

Please follow me

Answer:

La pendiente de la recta L es [tex]\frac{3}{2}[/tex].

Step-by-step explanation:

La recta está presentada en su forma implícita, es decir, que está bajo la forma:

[tex]f(x,y) = 0[/tex]

Para determinar la pendiente de la recta, se debe transformarla a su forma explícita, cuya fórmula es:

[tex]y = m \cdot x + b[/tex]

Donde:

[tex]x[/tex] - Variable independiente, adimensional.

[tex]y[/tex] - Variable dependiente, adimensional.

[tex]m[/tex] - Pendiente, adimensional.

[tex]b[/tex] - Intercepto, adimensional.

Entonces:

[tex]3\cdot x - 2\cdot y + 1 = 0[/tex]

[tex]2\cdot y = 3\cdot x +1[/tex]

[tex]y = \frac{3}{2}\cdot x + \frac{1}{2}[/tex]

Por simple inspección, se determina que la pendiente de la recta L es [tex]\frac{3}{2}[/tex].

Answer:

The expression = [tex] \frac{40}{y - 16} [/tex]

Value of the expression = 4 (when y is 20)

Step-by-step explanation:

Quotient simply means the result you get when you divide two numbers. Thus, dividend (the numerator) ÷ divisor (the denominator) = quotient.

From the information given to us here,

the dividend = 40

the divisor = y - 16

The quotient = [tex] \frac{40}{y - 16} [/tex]

There, the expression would be [tex] \frac{40}{y - 16} [/tex]

Find the value of the expression when y = 20.

Plug in 20 for y in the expression and evaluate.

[tex] \frac{40}{y - 16} [/tex]

[tex] = \frac{40}{20 - 16} [/tex]

[tex] = \frac{40}{4} = 10 [/tex]

The value of the expression, when y is 20, is 4.

Answer:

see below

Step-by-step explanation:

the simple answer is -270000

Answer:

The third option.

Step-by-step explanation:

Mathematical induction is a 2 step mathematical technique which is used to prove a statement, a formula or a theorem is true for every natural number.

Step 1 (Base step) - It proves that a statement is true for the initial value.

Step 2 (Inductive step) - It proves that if the statement is true for the nth iteration (or number n), then it is also true for (n + 1)th iteration (or number n + 1)

Hope this helps.

Please mark Brainliest.

Answer:

A method of improving statments

Step-by-step explanation:

"Mathematical Induction is a mathematical technique which is used to prove a statement, a formula or a theorem is true for every natural number."

Answer:

160 miles

Step-by-step explanation:

We can use a ratio to solve

220 miles         x miles

--------------- = ----------------------

5.5 hours          4 hours

Using cross products

220 *4 = 5.5x

880 = 5.5x

Divide each side by 5.5

880/5.5 = x

160 miles

Answer:

[tex]\large \boxed{\mathrm{C. \ 160 \ miles}}[/tex]

Step-by-step explanation:

We can solve this problem by ratios.

Let x be the missing value.

[tex]\displaystyle \frac{220}{5.5} =\frac{x}{4}[/tex]

Cross multiply.

[tex]5.5 \times x = 220 \times 4[/tex]

[tex]5.5x=880[/tex]

Divide both sides by 5.5.

[tex]\displaystyle \frac{5.5x}{5.5} =\frac{880}{5.5}[/tex]

[tex]x=160[/tex]

Answer:

D question,somewhat confusing, itsit's like simultaneous equation,but values are different

Answer:

x = 4 + 2y/3

Step-by-step explanation:

Answer:

Explained below.

Step-by-step explanation:

Let X = systolic blood pressure measurements.

It is provided that, [tex]X\sim N(\mu=80,\sigma^{2}=3^{2})[/tex].

(a)

Compute the percentage of measurements that are between 71 and 89 as follows:

[tex]P(71<X<89)=P(\frac{71-80}{3}<\frac{X-\mu}{\sigma}<\frac{89-80}{3})[/tex]

                        [tex]=P(-3<Z<3)\\=P(Z<3)-P(Z<-3)\\=0.99865-0.00135\\=0.9973[/tex]

The percentage is, 0.9973 × 100 = 99.73%.

Thus, the percentage of measurements that are between 71 and 89 is 99.73%.

(b)

Compute the probability that a person's blood systolic pressure measures more than 89 as follows:

[tex]P(X>89)=P(\frac{X-\mu}{\sigma}>\frac{89-80}{3})[/tex]

                [tex]=P(Z>3)\\=1-P(Z<3)\\=1-0.99865\\=0.00135\\\approx 0.0014[/tex]

Thus, the probability that a person's blood systolic pressure measures more than 89 is 0.0014.

(c)

Compute the probability that a person's blood systolic pressure being at most 75 as follows:

Apply continuity correction:

[tex]P(X\leq 75)=P(X<75-0.5)[/tex]

                [tex]=P(X<74.5)\\\\=P(\frac{X-\mu}{\sigma}<\frac{74.5-80}{3})\\\\=P(Z<-1.83)\\\\=0.03362\\\\\approx 0.034[/tex]

Thus, the probability that a person's blood systolic pressure being at most 75 is 0.034.

(d)

Let x be the blood pressure required.

Then,

P (X < x) = 0.15

⇒ P (Z < z) = 0.15

⇒ z = -1.04

Compute the value of x as follows:

[tex]z=\frac{x-\mu}{\sigma}\\\\-1.04=\frac{x-80}{3}\\\\x=80-(1.04\times3)\\\\x=76.88\\\\x\approx 76.9[/tex]

Thus, the 15% of patients are expected to have a blood pressure below 76.9.

(e)

A z-score more than 2 or less than -2 are considered as unusual.

Compute the z score for [tex]\bar x[/tex] as follows:

[tex]z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}[/tex]

  [tex]=\frac{84-80}{3/\sqrt{3}}\\\\=2.31[/tex]

The z-score for the mean blood pressure measurement of 3 patients is more than 2.

Thus, it would be unusual.

Answer:

17 miles

Step-by-step explanation:

4+5+5+3=17

Answer: -9/5

Step-by-step explanation: To find the slope, we must understand that the slope of a line is defined as the ratio rise/run.

The rise is the vertical direction of the line and the

run is the horizontal direction of the line.

So to start, I am going to pick 2 points on this line.

You want to find points where the line crosses the four corners.

In the diagram, those would be the points (-4, 5) and (1, -4).

Now, we can use slope formula.

Slope = y₂ - y₁ / x₂ - x₁

So we have -4 - 5/1 - -4 which simplifies to -9/5.

So the slope is -9/5.

Answer:

the answer is -9/5 100%

Step-by-step explanation:

Answer:

[tex] \frac{1}{3} [/tex]Rational number as denominator is not equal to zero and numerator is a integer.

Rational numbers. denoted by [tex] \mathbb Q[/tex]

1/3 is clearly not a natural number or integer.

it is a fraction, =0.333 , it fits the definition of rational number ([tex] \frac pq [/tex]).

Answer:

7

Step-by-step explanation:

First plug in the variable amounts so the expression now looks like this:

(3 × 4 - 12) + 1/2(4 × 6 - 10)

Now, start by solving the multiplication parts first, so it now looks like this:

(12 - 12) + 1/2(24 - 10)

Now, apply the rules of order of operation, so start by solving what's in parenthesis. It should now look like this: (0) + 1/2(14)

Next, solve the multiplication part, so it now looks like this: 0 + 7

Solve that and the answer is 7.

Answer:

Step-by-step explanation:

from the question,

the mean 14

the standard deviation is 3

and sample size is 10.

since the n which is the sample size is 10, then the distribution is mound shaped.

why?

this is due to the fact that the random variable from which we took the sample is mound shaped.

The sampling distribution of the mean is normally distributed although the question says the random variable is not normally distributed. so the shape is bell shaped and normally distributed.

the standard deviation of the mean is

3/√10

= 0.948

Answer:

486

Step-by-step explanation:

Hello!

To find the surface area of a cube we use the equation

[tex]S = 6a^{2}[/tex]

S is the surface area

a is the side length

Put what we know into the equation

[tex]S = 6*9^{2}[/tex]

Solve

S = 6 * 81

S = 486

Hope this Helps!

Answer:486[tex]ft^{2}[/tex]

Step-by-step explanation:

surface area= 6[tex]l^{2}[/tex]

l=9

sa=6 ([tex]9^{2}[/tex])= 6 x 81=486[tex]ft^{2}[/tex]

Answer:

0.90415

Step-by-step explanation:

Given the following :

Arrival rate = mean(μ) = 24

Probability that at most 30 customers arrive in the next hour:

The poisson distribution formula :

P(x, μ) = [(e^-μ) * (μ^x)] / x!

Where :

e = euler's constant

P(x ⩽ 30) = p(0) + p(1) + p(2) +.... + p(30)

Using the online poisson probability distribution calculator :

P(x ⩽ 30, 24) = 0.90415

Therefore there is about 90.4% probability that at most 30 customers will arrive in the next hour.

Answer:

19 purses

Step-by-step explanation:

Set up an inequality where x represents the number of purses:

127 [tex]\geq[/tex] 7x

Solve for x by dividing each side by 7:

18.14 [tex]\geq[/tex] x

Round up to 19 because purses have to be whole

So, 19 purses have to be sold.

Answer: 3

Step-by-step explanation:

first, we know that:

1 + 2 + 3 + 4 +5 +6 = 21

Now, which two numbers we should take out in order to have 15?

we can remove the 2 and the 4, or the 1 and the 5.

so here we have two possibilities, 2 and 4 are opposite, or 1 and 5 are opposite (they are located in opposite faces of the die)

in the other arrange, we have that removing two numbers we should get 12.

in order to reach 12, we should remove two numbers that add 9 together.

those can be 4 and 5, or 6 and 3.

Now, notice that in the first restriction we have that:

Or 2 and 4 are opposite,

or 1 and 5 are opposite.

So 4 and 5 can never be opposite, so we should have that 6 and 3 are opposite.

Then we can affirm that the value that appears in the face opposite to the 6, is the 3.

Answer:

[tex]\dfrac{-14}{9}[/tex].

Step-by-step explanation:

The given number is [tex]-1.\overline{5}[/tex].

We need to find a rational number in fraction form that is equivalent to given number.

Let [tex]x=-1.\overline{5}[/tex]

[tex]x=-1.555...[/tex]     ...(1)

Multiply both sides by 10.

[tex]10x=-15.555...[/tex]  ...(2)

Subtracting (1) from (2), we get

[tex]10x-x=-15.555...-(-1.555...)[/tex]

[tex]9x=-14[/tex]

Divide both sides by 9.

[tex]x=\dfrac{-14}{9}[/tex]

Therefore, the required rational number is [tex]\dfrac{-14}{9}[/tex].

Answer:

[tex]f(x) =3\,*\,\,4^x[/tex]

Step-by-step explanation:

to find the equation of an exponential function, just points on the function's graph  are needed.

Recall that the exponential function has a general expression given by:

[tex]f(x) = a \,e^{b\,x}[/tex]

so we impose the condition for the function going through the first point (0,3) as:

[tex]f(0) = a \,e^{b\,(0)}= 3\\a\,e^0=3\\a\,(1)=3\\a = 3[/tex]

Now,knowing the parameter a, we can find the parameter b using the other point:

[tex]f(1) = 3 \,e^{b\,x}= 12\\3\,e^{b\,(1)}=12\\e^b=12/3\\e^b=4\\b=ln(4)[/tex]

Therefore, the function can be written as:

[tex]f(x) = 3 \,e^{ln(4)\,x}=3\,\,\,4^x[/tex]

Answer:

C)

h(x) = 3(4)x

Answer:

(A) The probability that a male spent less than $210 online before deciding to visit a store is 0.0668.

(B) The probability that a male spent between $270 and $300 online before deciding to visit a store is 0.0655.

(C) Ninety percent of the amounts spent online by a male before deciding to visit a store is less than $265.632.

Step-by-step explanation:

We are given that the reports indicate that men spend an average of $240 online before they decide to visit a store. If the spending limit is normally distributed and the standard deviation is $20.

Let X = the spending limit

The z-score probability distribution for the normal distribution is given by;

                           Z  =  [tex]\frac{X-\mu}{\sigma}[/tex]  ~ N(0,1)

where, [tex]\mu[/tex] = mean spending limit = $240

           [tex]\sigma[/tex] = standard deviation = $20

So, X ~ Normal([tex]\mu=\$240,\sigma^{2} =\$20^{2}[/tex])

(A) The probability that a male spent less than $210 online before deciding to visit a store is given by = P(X < $210)

     P(X < $210) = P( [tex]\frac{X-\mu}{\sigma}[/tex] < [tex]\frac{\$210-\$240}{\$20}[/tex] ) = P(Z < -1.50) = 1 - P(Z [tex]\leq[/tex] 1.50)

                                                            = 1 - 0.9332 = 0.0668

The above probability is calculated by looking at the value of x = 1.50 in the z table which has an area of 0.9332.

(B) The probability that a male spent between $270 and $300 online before deciding to visit a store is given by = P($270 < X < $300)

     P($270 < X < $300) = P(X < $300) - P(X [tex]\leq[/tex] $270)

     P(X < $300) = P( [tex]\frac{X-\mu}{\sigma}[/tex] < [tex]\frac{\$300-\$240}{\$20}[/tex] ) = P(Z < 3) = 0.9987

     P(X [tex]\leq[/tex] $270) = P( [tex]\frac{X-\mu}{\sigma}[/tex] [tex]\leq[/tex] [tex]\frac{\$270-\$240}{\$20}[/tex] ) = P(Z [tex]\leq[/tex] 1.50) = 0.9332

The above probability is calculated by looking at the value of x = 3 and x = 1.50 in the z table which has an area of 0.9987 and 0.9332 respectively.

Therefore, P($270 < X < $300) = 0.9987 - 0.9332 = 0.0655.

(C) Now, we have to find ninety percent of the amounts spent online by a male before deciding to visit a store is less than what value, that is;

         P(X < x) = 0.90     {where x is the required value}

         P( [tex]\frac{X-\mu}{\sigma}[/tex] < [tex]\frac{x-\$240}{\$20}[/tex] ) = 0.90

         P(Z < [tex]\frac{x-\$240}{\$20}[/tex] ) = 0.90

In the z table, the critical value of z that represents the bottom 90% of the area is given as 1.2816, i.e;

                     [tex]\frac{x-\$240}{\$20}=1.2816[/tex]

                     [tex]x-240=1.2816\times 20[/tex]

                     [tex]x=240 + 25.632[/tex]

                     x = 265.632

Hence, Ninety percent of the amounts spent online by a male before deciding to visit a store is less than $265.632.