<u><em>Answer:</em></u>
volume of sphere = 288π ft³
<u><em>Explanation:</em></u>
volume of sphere = 
where pi is a constant and r is the radius of the sphere
<u>We are given that: </u>
The diameter of the sphere is 12 ft.
<u>This means that</u> the radius = 
<u>Substitute with the radius in the above equation to get the volume as follows:</u>
volume = 
ft³
Hope this helps :)
In constructing the equation, you need to know the following:
1. What don't we know? How many minutes you must talk to have the same cost for both calling plans. So, let x be the number of minutes.
2. What do we know? Plan 1 charges $17.50 per month plus $0.17 per minute used and Plan 2 charges $32 per month plus $0.07 per minute used.
So the equation must look like this: 17.50 + .17x = 32 + 0.07x
Solving the equation:
1. Multiply both sides by 100
(100) 17.5 + .17x = 32 + 0.07x (100)
1750 + 17x = 3200 + 7x
2. Subtract 1750 from both sides
1750 + 17x - 1750 = 3200 + 7x - 1750
17x = 7x +1450
3. Subtract 7x from both sudes
17x - 7x = 7x + 1450 - 7x
10x = 1450
4. Divide both sides by 100
10x / 10 = 1450/10
x= 145 minutes
145 minutes is the number of minutes you must talk to have the same cost for both calling plans.
Answer:
a-
y=80
x=18
b-
y=24
x=6
(might have to recheck letter a)
40 years if the rate stays the same
