Multiple choice

$A$ can do a piece of work in $15$ days. $B$ is $50\%$ more efficient than $A$. $B$ can finish it in

  1. $10$ days
  2. $7 \dfrac { 1 } { 2 }$ days
  3. $12$ days
  4. $12 \frac { 1 } { 2 }$ days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If B is 50% more efficient than A, B's efficiency is 1.5 times A's. Time taken by B = Time taken by A / 1.5 = 15 / 1.5 = 10 days.

AI explanation

Because efficiency and time are inversely proportional, B being 50% more efficient means the ratio of A's efficiency to B's efficiency is 100 to 150, or 2 to 3. The ratio of their times taken is therefore 3 to 2. If A takes 15 days, multiplying by the inverse fraction gives 15 * (2/3) = 10 days. The correct result is 10 days.

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