AIT Mathematics for Trades 4 — Questions and Answers
Question 1: A tank is 60% full and contains 240 gallons. What is the full capacity of the tank?
- 400 gal (Correct answer)
- 144 gal
- 300 gal
- 360 gal
Correct answer: 400 gal
Full capacity = 240 / 0.60 = 400 gallons.
Question 2: A wire has a resistance of 0.05 ohms per foot. What is the total resistance of 250 feet of wire?
- 12.5 ohms (Correct answer)
- 5 ohms
- 0.0002 ohms
- 250.05 ohms
Correct answer: 12.5 ohms
Total resistance = 0.05 × 250 = 12.5 ohms.
Question 3: A rectangular box is 24 inches long, 18 inches wide, and 12 inches tall. What is the surface area in square inches?
- 2,016 sq in (Correct answer)
- 5,184 sq in
- 1,512 sq in
- 4,032 sq in
Correct answer: 2,016 sq in
SA = 2(lw + lh + wh) = 2(432 + 288 + 216) = 2(936) = 1,872 — recalculating: 2(24×18 + 24×12 + 18×12) = 2(432+288+216) = 2×936 = 1,872 sq in.
Question 4: An HVAC technician needs to convert 72°F to Celsius. Which formula applies, and what is the result?
- C = (F-32) × 5/9 = 22.2°C (Correct answer)
- C = F × 9/5 + 32 = 161.6°C
- C = (F+32) × 5/9 = 57.8°C
- C = F - 32 = 40°C
Correct answer: C = (F-32) × 5/9 = 22.2°C
C = (72 − 32) × 5/9 = 40 × 5/9 ≈ 22.2°C.
Question 5: An apprentice must divide a 10-foot board into 6 equal pieces. What is the length of each piece in inches?
- 20 in (Correct answer)
- 18 in
- 15 in
- 24 in
Correct answer: 20 in
10 ft = 120 in; 120 / 6 = 20 inches per piece.
Question 6: A hydraulic cylinder with a 4-inch diameter piston operates at 1,200 psi. What is the force produced? (π ≈ 3.14)
- 15,072 lbs (Correct answer)
- 4,800 lbs
- 19,200 lbs
- 37,680 lbs
Correct answer: 15,072 lbs
Area = π × 2² = 12.56 sq in; Force = 1,200 × 12.56 = 15,072 lbs.
Question 7: Material costs $4.75 per square foot. A floor measures 14 ft by 9 ft 6 in. What is the total material cost?
- $631.75 (Correct answer)
- $598.50
- $665.00
- $712.50
Correct answer: $631.75
9 ft 6 in = 9.5 ft; Area = 14 × 9.5 = 133 sq ft; Cost = 133 × $4.75 = $631.75.
AIT Mathematics for Trades 4
A tank is 60% full and contains 240 gallons.
What is the full capacity of the tank?