If 50% of a number is 150 and 30% of the same number is 90, find 80% of that number.

Answer:

[tex] \frac{ |a + x| }{2} - \frac{ |a - x| }{2} \\ \\ = \frac{ | - 2 - 6| }{2} - \frac{ | - 2 + 6| }{2} \\ \\ = \frac{ | - 8| }{2} - \frac{ |4| }{2} \\ \\ = \frac{8}{2} - \frac{4}{2} \\ \\ = 4 - 2 = 2[/tex]

Answer:

35

Step-by-step explanation:

Answer:

I will post 4,5 and 6 separately.

Answer:

√36/√16 is a rational number as it can be written as 6/4=3/2 which is rational

Answer:

her first step should be to multiply the coefficient of the first term by the constant   1 • -3 = -3

Step-by-step explanation:

i looked it up on tiger algebra lol

Answer:

No, the table is not linear.

Step-by-step explanation:

Between the x and y there has to be a constant rate. There is no constant rate.

Answer:

First time=7hours

First speed=990km/hour

First distance=first time×first speedD=(

S×T)

D=990km/hr×7hrs

D=6930km.

Second time=6&14min.

Second speed=920km/hr

Second distance=second speed×second time (D=s×t)

D=920km/hr×6&14min.

D=1500

Total distance=6930+1500

=8430

Answer:

24

Step-by-step explanation:

2(54-6x)=73-7x

108-12x=73-7x

108-73=-7x+12x

35=5x

x=7

UW=73-7x=73-7(7) = 73-49 = 24

Answer:

8 weeks

Step-by-step explanation:

Given data

Matteo

Amount= $400

Spending per week= $10

Hence his balance after x weeks is given as

y=400-10x-------------1

Luca

Amount= $200

Spending per week= $15

Hence his balance after x weeks is given as

y=200+15x-------------2

Equate 1 and 2

400-10x=200+15x

collect like terms

400-200=15x+10x

200=25x

x= 200/25

x= 8 weeks

Hence it will take 8 weeks

Answer:

The area of the rectangle is increasing at a rate of 168 square centimeters per second.

Step-by-step explanation:

Geometrically speaking, the area of a rectangle ([tex]A[/tex]), in square centimeters, is described by following expression:

[tex]A = w\cdot l[/tex] (1)

Where:

[tex]w[/tex] - Width, in centimeters.

[tex]h[/tex] - Height, in centimeters.

By Differential Calculus, we find an expression for the rate of change of the area of the rectangle ([tex]\dot A[/tex]), in square centimeters per second:

[tex]\dot A = \dot w\cdot l + w\cdot \dot l[/tex] (2)

Where:

[tex]\dot w[/tex] - Rate of change of the width of the rectangle, in centimeters per second.

[tex]\dot l[/tex] - Rate of change of the length of the rectangle, in centimeters per second.

If we know that [tex]w = 12\,cm[/tex], [tex]l = 15\,cm[/tex], [tex]\dot w = 4\,\frac{cm}{s}[/tex] and [tex]\dot l = 9\,\frac{cm}{s}[/tex], then the rate of change of the area of the rectangle is:

[tex]\dot A = \dot w\cdot l + w\cdot \dot l[/tex]

[tex]\dot A = 168\,\frac{cm^{2}}{s}[/tex]

The area of the rectangle is increasing at a rate of 168 square centimeters per second.

Answer:

area of one pie : πr² = π d²/4 = π× 2²/4 = π ≈ 3.14

Answer:

4/6  8/12

Step-by-step explanation:

Answer: C

Step-by-step explanation:

Answer: (1/4,31)

Step-by-step explanation: Use the formula x = − b/2a a to find the maximum and minimum.

Answer:

The t-distribution is used, as we have the standard deviation of the sample.

The 95% confidence interval for the population mean time wasted is between 7.12 hours and 8.88 hours.

Step-by-step explanation:

We have the standard deviation for the sample, which meas that the t-distribution should be used to solve this question.

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 81 - 1 = 80

95% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 80 degrees of freedom(y-axis) and a confidence level of [tex]1 - \frac{1 - 0.95}{2} = 0.975[/tex]. So we have T = 1.99

The margin of error is:

[tex]M = T\frac{s}{\sqrt{n}} = 1.99\frac{4}{\sqrt{81}} = 0.88[/tex]

In which s is the standard deviation of the sample and n is the size of the sample.

The lower end of the interval is the sample mean subtracted by M. So it is 8 - 0.88 = 7.12 hours.

The upper end of the interval is the sample mean added to M. So it is 8 + 0.88 = 8.88 hours.

The 95% confidence interval for the population mean time wasted is between 7.12 hours and 8.88 hours.

Answer: 20% of 90 = 18

Answer:

90%

Step-by-step explanation:

i hope this helps:)

Answer:

1728

Step-by-step explanation:

if its a cube then all sides are the same length. you need to times to base width and height. so it will be 12 times 12 times 12 which is 1728.

Answer:

the answer is c

Step-by-step explanation:

Answer:

c

Step-by-step explanation:

Answer:

∠ BDC = 30°

Step-by-step explanation:

The angle on the circle is half the measure of the central angle subtended by the arc BC

∠ BDC = [tex]\frac{1}{2}[/tex] × 60° = 30°

Answer:

x=17

Step-by-step explanation:

4x+8+44+60=180

4x+112=180

4x=180-112

4x=68

x=68/4

x=17

Answer:

the answer is C.  5 cubic in

Step-by-step explanation:

V = LWH

length is 2 (1/2 in)

width is 5 (1/2 in)

height is 4 (1/2 in)

V = (2/2) (5/2) (2)

V = 1 * 5/2 * 2

V = 5 cubic in

Answer:

=2−i

Step-by-step explanation:

Hope this helps :)

BRAINLIEST PLSSS I HAVE A LITTLE BIT POINTS :|

Answer: 2/3

Step-by-step explanation:

Answer: -2/3

Step-by-step explanation:

Hope This Help?

Please Mark Me brainly!

Answer:

a) The standard score associated with a gestation period of 13.8 months is of [tex]Z = -1[/tex]

b) 34% of whale pregnancies will have a gestation period between 13.8 and 15 months.

c) Since when [tex]X = 21[/tex], [tex]Z = 5 \geq 2[/tex], it would be unusual for a whale to have a gestation period of 21 months.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the zscore of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

If [tex]Z \geq 2[/tex] or [tex]Z \leq -2[/tex], the measure X is considered to be unusual.

According to a website, the mean gestation period for a whale is 15 months. Assume the distribution of gestation periods is Normal with a standard deviation of 1.2 months.

I corrected to 1.2 because it is what makes sense considering the questions.

This means that [tex]\mu = 15, \sigma = 1.2[/tex]

a. Find the standard score associated with a gestation period of 13.8 months

This is Z when X = 13.8. So

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{13.8 - 15}{1.2}[/tex]

[tex]Z = -1[/tex]

The standard score associated with a gestation period of 13.8 months is of [tex]Z = -1[/tex]

b. Using the Empirical Rule and your answer to part a, what percentage of whale pregnancies will have a gestation period between 13.8 and 15 months?

The standard score associated with a gestation period of 13.8 months is of [tex]Z = -1[/tex], which means that it is one standard deviation below the mean.

The normal distribution is symmetric, which means that of the approximately 68% of measures within one standard deviation of the mean, 68%/2 = 34% are within one standard deviation below the mean(in this case, 13.8) and the mean(in this case 15), and 34% are within the mean and one standard deviation above the mean.

So 34% of whale pregnancies will have a gestation period between 13.8 and 15 months.

c. Would it be unusual for a whale to have a gestation period of 21 months? Why or why not?

Let's find the z-score

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{21 - 15}{1.2}[/tex]

[tex]Z = 5[/tex]

Since when [tex]X = 21[/tex], [tex]Z = 5 \geq 2[/tex], it would be unusual for a whale to have a gestation period of 21 months.

Answer:

I) ∠2 and ∠5

Step-by-step explanation: