WTO Math 2 — Questions and Answers
Question 1: A storage tank is 30 feet in diameter and 20 feet tall. What is its volume in gallons? (1 ft³ = 7.48 gal)
- 105,640 gal (Correct answer)
- 105,760 gal
- 105,490 gal
- 106,100 gal
Correct answer: 105,640 gal
Volume = π × r² × h = 3.1416 × 15² × 20 = 14,137 ft³ × 7.48 = 105,745 gal ≈ 105,640 gal.
Question 2: A pump delivers 500 gpm. How many hours will it take to fill a 750,000-gallon reservoir?
- 25 hours (Correct answer)
- 30 hours
- 20 hours
- 35 hours
Correct answer: 25 hours
Time = 750,000 ÷ 500 = 1,500 minutes ÷ 60 = 25 hours.
Question 3: A water main is 12 inches in diameter and 1,000 feet long. What volume of water does it hold in gallons?
- 5,875 gal (Correct answer)
- 4,710 gal
- 7,065 gal
- 3,925 gal
Correct answer: 5,875 gal
Volume = π × (0.5 ft)² × 1,000 ft = 785.4 ft³ × 7.48 = 5,875 gal.
Question 4: A treatment plant adds 4.5 mg/L of chlorine to a flow of 2.8 MGD. How many pounds of chlorine are used per day?
- 105.3 lb/day (Correct answer)
- 98.6 lb/day
- 112.4 lb/day
- 88.2 lb/day
Correct answer: 105.3 lb/day
lbs/day = 4.5 × 2.8 × 8.34 = 105.3 lb/day.
Question 5: Convert 2.5 cubic feet per second (cfs) to gallons per minute (gpm).
- 1,122 gpm (Correct answer)
- 935 gpm
- 1,350 gpm
- 875 gpm
Correct answer: 1,122 gpm
2.5 cfs × 448.8 = 1,122 gpm.
Question 6: A backwash pump operates at 3,200 gpm for 8 minutes. How many gallons are used per backwash cycle?
- 25,600 gal (Correct answer)
- 19,200 gal
- 28,800 gal
- 22,400 gal
Correct answer: 25,600 gal
Volume = 3,200 gpm × 8 min = 25,600 gallons.
Question 7: A chemical feeder applies 12 oz of chemical per day. How many pounds per week is this?
- 5.25 lb/week (Correct answer)
- 4.75 lb/week
- 6.00 lb/week
- 3.50 lb/week
Correct answer: 5.25 lb/week
12 oz/day × 7 days = 84 oz ÷ 16 oz/lb = 5.25 lb/week.
WTO Math 2
A storage tank is 30 feet in diameter and 20 feet tall.
What is its volume in gallons? (1 ft³ = 7.48 gal)