Multiple choice

A takes thrice as much time as B to finish a job. B and C together take one quarter of the time to finish the job that A takes working alone. Moreover, in order to finish the job, A takes 5 days more than the number of days taken by three of them working together. In how many days will C take to finish the job working alone?

  1. 25/12

  2. 25/4

  3. 25/2

  4. 25

  5. NA
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let A take 3x days, B take x days. B+C take (1/4)*3x = 0.75x days. 1/C = 1/0.75x - 1/x = (1 - 0.75) / 0.75x = 0.25 / 0.75x = 1/3x. So C takes 3x days. A, B, C together take 1/(1/3x + 1/x + 1/3x) = 1/(5/3x) = 0.6x. Given A = (A+B+C) + 5 => 3x = 0.6x + 5 => 2.4x = 5 => x = 5/2.4 = 25/12. C takes 3x = 3 * (25/12) = 25/4 days.

Keep practicing — related questions