Multiple choice

A and B together can do a piece of work in 35 days, while A alone can do it in 60 days. How long would B alone to it?

  1. $74$ days
  2. $88$ days
  3. $54$ days
  4. $84$ days
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let total work be 1 unit. Rate of A+B = 1/35. Rate of A = 1/60. Rate of B = 1/35 - 1/60 = (12-7)/420 = 5/420 = 1/84. So B takes 84 days.

AI explanation

Using the standard work rate formula, the combined daily work of A and B is 1/35. Since A alone completes 1/60 of the work per day, B's daily work rate is 1/35 minus 1/60. Finding a common denominator of 420 gives 12/420 minus 7/420, resulting in 5/420 or 1/84. Therefore, B alone will complete the work in 84 days.

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