Three friends A, B and C are employed to make pastries in a bakery. Working…
2025
Three friends A, B and C are employed to make pastries in a bakery. Working individually, they can make 60, 30 and 40 pastries respectively in an hour. They decided to work together but due to lack of resources, they had to work on shifts of 30 minutes. Find the time taken to make 185 pastries.
- A.
4 hours
- B.
3 hours 45 minutes
- C.
4 hours 15 minutes
- D.
5 hours
Attempted by 17 students.
Show answer & explanation
Correct answer: C
Answer: 4 hours 15 minutes
Explanation:
Work rates (per hour): A = 60, B = 30, C = 40. In 30 minutes they make A = 30, B = 15, C = 20 pastries respectively.
Sequence of shifts: each person works 30 minutes in turn (first A, then B, then C). One full rotation (A then B then C) lasts 1 hour 30 minutes and produces 30 + 15 + 20 = 65 pastries.
Two full rotations (2 × 1 hour 30 minutes = 3 hours) produce 2 × 65 = 130 pastries.
Continue after 3 hours: next 30-minute shift is A → adds 30 → total 160 at 3 hours 30 minutes.
Next 30-minute shift is B → adds 15 → total 175 at 4 hours.
Remaining pastries needed: 185 − 175 = 10. C produces 20 pastries in a 30-minute shift, so producing 10 pastries requires half that shift: 15 minutes.
Total time = 4 hours + 15 minutes = 4 hours 15 minutes.