Multiple choice

A and B can do a piece of work in 30 days and 40 days respectively after 3 days start of work A leave the job in how many days B can do the remaining of work alone.

  1. 33 days

  2. 26 days

  3. 13 days

  4. 30 days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A's work rate is 1/30 per day. B's work rate is 1/40 per day. In 3 days together, they complete 3(1/30 + 1/40) = 3(7/120) = 7/40 of the work. Remaining work is 1 - 7/40 = 33/40. B alone needs (33/40) ÷ (1/40) = 33 days to finish the remaining work. Option A is correct.

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