Multiple choice

A is thrice as good a worker as B and takes 8 days less to do a piece of work than B. In how many days can B do the work?

  1. 16

  2. 8

  3. 12

  4. 10
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

If A is thrice as efficient as B, then A's work rate is 3x B's rate. Let B take x days, so A takes x-8 days. Since work = rate × time, and work done is the same: 3(x-8) = x, giving x = 12 days. Alternatively, use the formula: if A is k times efficient and takes d days less, then B takes kd/(k-1) = 3×8/2 = 12 days.

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