17 trainees can do as much work as 4 experts can do in a day. It takes 12 experts and 9 trainees 5 days to dig a pond. How many trainees will one need alongside 4 experts to dig a similar pool in 15 days?
17 trainees can do as much work as 4 experts can do in a day. It takes 12 experts and 9 trainees 5 days to dig a pond. How many trainees will one need alongside 4 experts to dig a similar pool in 15 days? Correct Answer 3
Let, a trainee’s efficiency = x/day
An expert’s efficiency = y/day
According to the question,
⇒ 17x = 4y
⇒ x = 4y/17 ----(1)
According to the question,
⇒ 5(9x + 12y) = 1
⇒ 5(36y/17 + 12y) = 1
⇒ (36y + 204y) × 5/17 = 1
⇒ 1200y = 17
⇒ y = 17/1200
∴ x = 4/17 × 17/1200 = 4/300
Let, number of trainees required = k
According to the question,
⇒ 15 × = 1
⇒ 17/20 + k/20 = 1
⇒ k + 17 = 20
⇒ k = 3
∴ 3 trainees will be needed
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Feb 20, 2025