Multiple choice

To do a certain work, the ratio of efficiencies of X and Y is 5 : 4. Working together, they can complete the same work in 10 days. Y alone starts the work and leaves after 5 days. The remaining work will be completed by X alone in ?

  1. 14 days

  2. 12 days

  3. 15 days

  4. 10 days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let X's efficiency = 5k, Y's efficiency = 4k. Combined efficiency = 9k. Together they complete work in 10 days, so total work = 90k. Y works alone for 5 days, completing 20k. Remaining work = 70k. X alone does 5k per day, so time needed = 70k/5k = 14 days. Option A is correct.

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