BARB Work Rate 2 — Questions and Answers
Question 1: Soldier A can complete a task in 6 hours alone. Soldier B can complete the same task in 3 hours alone. How long will they take working together?
- 1.5 hours
- 4 hours
- 2 hours (Correct answer)
- 2.5 hours
Correct answer: 2 hours
A's rate = 1/6, B's rate = 1/3; Combined = 1/6 + 2/6 = 3/6 = 1/2 task per hour; Time = 2 hours.
Question 2: A factory produces 500 units in 10 hours. How many units are produced in 7 hours?
- 360
- 350 (Correct answer)
- 300
- 400
Correct answer: 350
Rate = 500 ÷ 10 = 50 units/hr; In 7 hrs = 50 × 7 = 350 units.
Question 3: Three engineers each repair 8 vehicles per day. How many vehicles do they repair in 5 days?
- 100
- 130
- 120 (Correct answer)
- 110
Correct answer: 120
Daily total = 3 × 8 = 24 vehicles; Over 5 days = 24 × 5 = 120 vehicles.
Question 4: A soldier completes 1/4 of a task each hour. How long does the full task take?
- 2 hours
- 3 hours
- 5 hours
- 4 hours (Correct answer)
Correct answer: 4 hours
If 1/4 is done per hour, the full task takes 4 hours.
Question 5: Worker A completes a job in 8 hours and Worker B completes the same job in 4 hours. How long do they take working together?
- 2 hours 40 min (Correct answer)
- 3 hours
- 2 hours
- 3 hours 20 min
Correct answer: 2 hours 40 min
A's rate = 1/8, B's rate = 1/4 = 2/8; Combined = 3/8 per hr; Time = 8/3 ≈ 2 hrs 40 min.
Question 6: If 6 soldiers clean 18 rifles in 3 hours, how many rifles can 9 soldiers clean in the same time?
- 24
- 30
- 27 (Correct answer)
- 21
Correct answer: 27
Each soldier cleans 18 ÷ 6 = 3 rifles in 3 hours; 9 soldiers clean 9 × 3 = 27 rifles.
BARB Work Rate 2
Soldier A can complete a task in 6 hours alone.
Soldier B can complete the same task in 3 hours alone.
How long will they take working together?