Multiple choice

Sai can do any work in 17 days, while Bindu can do it in 51 days. Sai works on the first day, Bindu works on the second day and this sequence continues till the work is over. How many days did it take to complete the work ?

  1. 13 days

  2. 25 days

  3. 14 days

  4. 11 days
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In 2 days, work done = 1/17 + 1/51 = 4/51. In 24 days, work = 24/2 × 4/51 = 48/51. Day 25: Sai does 1/17 ≈ 0.059, so total = 48/51 + 1/17 = 51/51 = 1. Work completes on day 25. Day 13 gives only 26/51 (half done), and 14 days gives 28/51, still incomplete.

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