Some helpers are engaged in a kitchen. Each helper can make either 2 large…
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Some helpers are engaged in a kitchen. Each helper can make either 2 large cakes or 35 small cakes per hour. The kitchen is available for 3 hours and 20 large cakes and 700 small cakes are needed. How many helpers are required ?
- A.
18
- B.
15
- C.
20
- D.
10
Attempted by 5 students.
Show answer & explanation
Correct answer: D
Key idea: Convert everything to the same unit (small-cake equivalents) or use each helper's 3-hour output.
Find per-helper output in 3 hours: each helper makes 2 large or 35 small per hour, so in 3 hours a helper makes 6 large or 105 small.
Convert large cakes to small-equivalents: since 6 large = 105 small, 1 large = 105 ÷ 6 = 17.5 small. So 20 large = 20 × 17.5 = 350 small-equivalents.
Total small-equivalents required = 350 (from large) + 700 (small) = 1050.
Each helper supplies 105 small-equivalents in 3 hours, so number of helpers = 1050 ÷ 105 = 10.
Answer: 10 helpers