Multiple choice

A can do 2/5 work in 20 days. Then, he is assisted by B to complete the remaining work in 12 days. In how much time can B alone do the work?

  1. 30 days

  2. 100 3 days

  3. 125 3 days

  4. 45 days

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A's rate is (2/5)/20 = 1/50 of the work per day. Together they complete 3/5 work in 12 days, so their combined rate is 1/20. B's rate is 1/20 - 1/50 = 3/100, giving B an individual time of 100/3 days.

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