Multiple choice

Two persons A and B can finish a piece of work in 60 days, while A, B, and C can finish the same work in 40 days. How many days will C alone take to finish the work?

  1. 80 days

  2. 90 days

  3. 100 days

  4. 110 days

  5. 120 days
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Let total work = LCM(60, 40) = 120 units. A + B's rate = 120/60 = 2 units/day. A + B + C's rate = 120/40 = 3 units/day. Therefore, C's rate = 3 - 2 = 1 unit/day. Time for C alone = 120/1 = 120 days. Option E is correct. Options A-D are common errors from incorrect rate calculations or LCM selection.

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