Answer:
You have a rectangular pool 15 X 30 X 5 feet
The floor of the pool is 15X30 = 450 ft2
Two sides are 5X15 = 2(75) = 150 ft2
Two sides are 5X30 = 2(150) = 300 ft2
Total area to be painted: 900 ft2
(900 ft2)/(250 ft2/gal) = 3.6 gallons
Since we can't purchase .6 gallons we
must purchase 4 gallons of paint
The volume of the pool is 15X30X5 = 2250 ft3
1 ft3 = 7.48 gallons
2250(7.48) = 16,830 gallons of water