my question is big so look in the detail flap?

Question

The depth of a pool varies directly with how many gallons of water it will hold. If a 6 foot deep pool holds 10,000 gallons of water, a pool that holds 12,500 gallons of water should be __________inches deep, according to this theory.

Answer 1

If the length and width of the pool are always the same, then the volume of water the pool can hold is proportional to the depth.

If 6 feet deep gives 10,000 gallons
and X feet deep gives 12,500 gallons

Then the ratio of volumes should be the same as the ratio of depths:

12500 / 10000 = X / 6
1.25 = X / 6
7.5 = X

So, the pool is 7.5 feet deep, which is 90 inches deep.

Answer 2

so 6/10,000 = x/12,500
cross multiply: 6*12,500 = x*10,000
75,000 = x*10,000
x= 7.5 ft.
x = 7.5*12 inches
x = 90 inches