Multiple choice

A and B can do a piece of work in 10 and 15 days respectively. They began the work together but A leaves after some days and B completed the remaining work in 8 days. Number of days after which A left the job?

  1. 2 4/5 days

  2. 4 ½ days

  3. 3 ¾ days

  4. 5 1/3 days

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A does 1/10 work/day, B does 1/15 work/day. Let x be the days they worked together. (1/10 + 1/15) * x + (1/15) * 8 = 1. (3/30 + 2/30) * x + 8/15 = 1 => 5/30 * x = 7/15 => 1/6 * x = 7/15 => x = 42/15 = 14/5 = 2.8 days.

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