16 because 25% of 20 is 4 so 4 question were choice B. Then, I subtracted 20 by 4 and got 16. I hope that helped! :)
8,15,17 represents
(17)^2=289
(15)^2=225
(8)^2=64
i.e. (17)^2=(15)^2+(8)^2
By converse of Pythagoras theorem
This ∆ is a right angled ∆
ANSWER
The swimming pool can hold 1,000,000 cubic feet of water.
EXPLANATION
The capacity of water the pool holds is the volume of water in the swimming pool.
The swimming pool is rectangular, therefore its volume can be calculated using the formula,

where l=1000ft is the length, w=100ft is the width and h=10ft is the height of the pool.
We substitute all these values into the formula to get:

The swimming pool can hold 1,000,000 cubic feet of water.