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M takes 60% more time than N to complete a wall. If together they complete the wall in 24 days, then how many days will N alone take to complete it?
- A36
- B39
- C42
- D34
Answer not set
Discussion 1
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CCommunity
Let N complete a wall in 100 days
M complete a wall = 100 × (160/100) = 160 days
So, Ratio of their time (N ? M) = 100 ? 160 = 5 ? 8
We know, efficiency is inversely proportional to time
Thus, Ratio of their efficiency (N ? M) = 8 ? 5
Time taken by them to complete the wall together = 24 days
⇒ Total work done by them = (8 + 5) × 24 = 13 × 24 = 312
∴ Time taken by N alone to complete the wall = 312/8 = 39 days
M complete a wall = 100 × (160/100) = 160 days
So, Ratio of their time (N ? M) = 100 ? 160 = 5 ? 8
We know, efficiency is inversely proportional to time
Thus, Ratio of their efficiency (N ? M) = 8 ? 5
Time taken by them to complete the wall together = 24 days
⇒ Total work done by them = (8 + 5) × 24 = 13 × 24 = 312
∴ Time taken by N alone to complete the wall = 312/8 = 39 days