Mathematical Reasoning
Mr Brown made 840 spare parts in 12 hours. At this pace, how many hours will he need to make 3150 spare parts?
Question 1 · Multiple choice
Question
Mr Brown made 840 spare parts in 12 hours. At this pace, how many hours will he need to make 3150 spare parts?
Options
- A.35
- B.40
- C.45
- D.50
- E.55
Correct answer
Explanation
Step 1: Find Mr Brown's rate
840 parts in 12 hours.
Rate = 840 ÷ 12 = 70 parts per hour
Step 2: Find the time for 3 150 parts
Time = Total parts ÷ Rate = 3 150 ÷ 70
= 45 hours
(70 × 40 = 2 800; 3 150 − 2 800 = 350; 350 ÷ 70 = 5; total = 40 + 5 = 45)
Check: 70 × 45 = 3 150 ✓
Answer: Mr Brown needs 45 hours