The radioactive isotope of lead, Pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.3 hours. If 1 gram of this isotope is present initially, how long will it take for 70% of the lead to decay? (Round your answer to two decimal places.)

Answer:

54

Step-by-step explanation:

16.4= 16

12.8= 13

9.6= 10

14.6=15

16 + 13 +10 +15 = 54

Answer:

4

Step-by-step explanation:

in y=mx+b, the "b" is the y-intercept

Answer:

4

it's in y = mx + b form, where b is the y-intercept

Answer:

17 boys and 11 girls

Step-by-step explanation:

Create a system of equations where b is the number of boys and g is the number of girls:

b + g = 28

b = g + 6

Solve by substitution, by substituting the second equation into the first one:

b + g = 28

(g + 6) + g = 28

2g + 6 = 28

2g = 22

g = 11

So, there are 11 girls.

Since there are 6 more boys than girls, there are 17 boys.

So, there are 17 boys and 11 girls in the class.

Answer:

[tex]3a {x}^{4} [/tex]

Step-by-step explanation:

remeber that idical laws

[tex] {x}^{a} \times {x}^{b} = {x}^{a + b} [/tex]

Answer:

Step-by-step explanation:

Convert to a mixed number by placing the numbers to the right of the decimal over 100. Reduce the fraction.

Answer:

87/100

Step-by-step explanation:

Answer:

[tex]AC = 28[/tex]

Step-by-step explanation:

Given

[tex]AB = 16[/tex]

[tex]BC = 12[/tex]

Required

Determine AC

Since A, B and C are collinear, then:

[tex]AC = AB + BC[/tex]

So, we have:

[tex]AC = 16 + 12[/tex]

[tex]AC = 28[/tex]

Answer:

11

Step-by-step explanation:

Multiply 44 by 3 to get the amount of eggs you need total, then divide it by 12 for each dozen of cartons you’ll need to buy. The end result is 11.

D- The new graph would be steeper than the original graph, and the y- intercept would shift up 3 units.

The purple line is y=-5x + 2

The pink line is y = -7x + 5

Answer:

f(n) = 4n + 16

Step-by-step explanation:

n is the nth number in the sequence

plug in the first 3 to check the rule:

4(1) + 16 = 4 + 16 = 20

4(2) + 16 = 8 + 16 = 24

4(3) + 16 = 12 + 16 = 28

it works

Answer:

39/89

Step-by-step explanation:

Answer:

7/25

Step-by-step explanation:

(sin) = opp/hyp

Answer: The width is 8cm

Step-by-step explanation:

39x38=1482

11856÷1482 = 8cm

Answer:

[tex]y=2x+5[/tex]

Step-by-step explanation:

Hi there!

Slope-intercept form: [tex]y=mx+b[/tex] where m is the slope and b is the y-intercept (the value of y when x is 0)

1) Determine the slope (m)

[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex] where two given points are [tex](x_1,y_1)[/tex] and [tex](x_2,y_2)[/tex]

Plug in the given points (-3,-1) and (1,7)

[tex]m=\frac{7-(-1)}{1-(-3)}\\m=\frac{7+1}{1+3}\\m=\frac{8}{4}\\m=2[/tex]

Therefore, the slope of the line is 2. Plug this into [tex]y=mx+b[/tex]:

[tex]y=2x+b[/tex]

2) Determine the y-intercept (b)

[tex]y=2x+b[/tex]

Plug in one of the given points and solve for b

[tex]7=2(1)+b\\7=2+b[/tex]

Subtract 2 from both sides to isolate b

[tex]7-2=2+b-2\\5=b[/tex]

Therefore, the y-intercept is 5. Plug this back into [tex]y=2x+b[/tex]:

[tex]y=2x+5[/tex]

I hope this helps!

Answer:

A discrete variable is a variable that can only take some selected given values from a given set, like x ∈ {x₁, x₂, ..., xₙ}

While a continuous variable can take any value in the range, like x ∈ {x₁, xₙ}.

1)  The weight of bags of apples, with 10 apples in each bag.

Here the weight depends on the number of apples in the bag, and we can have only whole numbers of apples in the bag, so this is clearly a discrete variable.

2) The number of times required for a modem to dial an internet provider before connecting.

Same as before, here we can have only a whole number of attempts, so this set is discrete.

3) Out of 10 times connecting to an internet provider, the average number of attempts necessary before connecting.

Here we will have an average of 10 integer numbers:

[tex]M = \frac{x_1 + x_2 + ... + x_{10}}{10}[/tex]

so here we have a kinda dense set of possible values, so we can think of this as a continuous variable.

4)  A pair of dice is rolled, and the sum to appear on the dice is recorded.

Here the possible values are whole numbers again, so we can not have values like 3.5, so again, this is a discrete variable.

Answer in fraction form = -3/2

Answer in decimal form = -1.5

=========================================

Work Shown:

[tex]m = \frac{g(b)-g(a)}{b-a}\\\\m = \frac{g(1)-g(-3)}{1-(-3)}\\\\m = \frac{0-6}{1-(-3)}\\\\m = \frac{0-6}{1+3}\\\\m = \frac{-6}{4}\\\\m = -\frac{3}{2}\\\\m = -1.5\\\\[/tex]

Effectively, we're finding the slope through the points (-3, 6) and (1, 0)

The g(b)-g(a) represents how y changes when going from x = a to x = b.

12? im not sure

i think u need to multiply 6 and 2 to get your answer.

Step-by-step explanation:

everything can be found in the picture

Answer:

x = 102

Step-by-step explanation:

The angles form a straight line

Angles that form a straight line add up to equal 180

Hence, x + 78 = 180

Subtract both sides by 78

180 - 78 = 102

78 - 78 cancels out

Were left with x = 102

Answer:

32

Step-by-step explanation:

14+6(9-6)

[9-6=3]

14+6x3

[6x3=18]

14+18

32

---

hope it helps

Answer:

14+6×(9-6)=32

Answer:

The 13th number in the Fibonacci sequence is 144.

Step-by-step explanation:

The sequence from the first to the 13th number is: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144.

[tex]\huge\boxed{\sf 144}[/tex]

A series of integers known as the Fibonacci sequence begins with a zero, is followed by a one, another one, and then a series of increasing numbers. Each number in the series equals the sum of the two numbers before it. Every succeeding pair of Fibonacci numbers has a quotient resembling the golden ratio.

[tex]\sf 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, \boxed{144}, 233, 377,...[/tex]

Answer: the top one

Step-by-step explanation:

Answer:

3 mi of fencing would be required to enclose this field.

Step-by-step explanation:

Here we are finding the perimeter of a field with given length and width.  We apply the perimeter formula P = 2L + 2W.  Substituting the given dimensions, we get:

P = 2(1 mi) + 2(0.5 mi), or

P = 2 mi + 1 mi = 3 mi

3 mi of fencing would be required to enclose this field.

Answer:

15840 feet of fencing = Perimeter = 15840ft

However, if fencing is 6ft or 10ft we need to divide by the length of each fence for panels.

See bold.

Step-by-step explanation:

6ft fencing = 5280/6 = 880 fences one length

880 x 2 = 1760 6ft fences 2 sides

0.5 x 1760 = 880

1760+ 880 = 2640 fences each 6ft

Total feet of fence = 2640 x 6 =15840 feet of fencing

Given:

A spinner is divided into 8 equal sections  where 3 are black, 4 are yellow, and 1 is red.

To find:

The probability of it landing either on a yellow or a red section.

Solution:

We have,

Total number of sections = 8

Black sections = 3

Yellow sections = 4

Red sections = 1

Now,

Either yellow or red sections = 4 + 1

                                                = 5

Now, the probability of it landing either on a yellow or a red section is:

[tex]\text{Required probability}=\dfrac{\text{Either yellow or red sections}}{\text{Total number of sections}}[/tex]

[tex]\text{Required probability}=\dfrac{5}{8}[/tex]

Therefore, the required probability is [tex]\dfrac{5}{8}[/tex].

Answer:

99

Step-by-step explanation:

10% = 66

5% = 33

66+33=99

Step-by-step explanation:

p^2+b^2=h^2

or, 16+9=h^2

or, 25=h^2

or h=5

again, p^2 +b^2=h^2

or, 25+b^2=36

or, b^2=11

or. b=√11 therefore b=x=√11

Answer:

This is a protractor question if you dont have one then try these on a calculator.

when angle is between two lines we need see where the hypotenuse is in the diagram and where is the adjacent.

And whether the triangle is right angle or not.

Try these

shift sin -1  x sin 9/6 (for opp/hyp)

shift sin -1  (9/6)   (for opp/hyp)

shift sin -1 x sin 6/9 (for opp/hyp)

shift sin -1 (6/9) (for opp/hyp)

shift cos -1 x cos 9/6 (for adj/hyp)

shift cos -1 (9/6) (for adj/hyp)

shift cos -1 x cos (6/9) (for adj/hyp)

shift cos -1 (6/9) (for adj/hyp)

shift tan -1 x tan (9/6) ( for opp/adj)

and so on....

Step-by-step explanation:

Answer:

12 meters

20cm*60 = 1200cm = 12 meters

100cm = 1m btw

Answer:

It is D...........nnnnnnn

Answer:

tan C is 90

tan B is 60

tan A is 60