Multiple choice

Two men and $7$ children complete a certain piece of work in $4$ days while $4$ men and $4$ children complete the same work in only $3$ days. The number of days required by $1$ man to complete the work is

  1. $60$ days
  2. $15$ days
  3. $6$ days
  4. $51$ days
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let M be the work of a man and C be the work of a child per day. From the problem, 2M + 7C = 1/4 and 4M + 4C = 1/3. Solving this system gives M = 1/15, meaning one man completes the work in 15 days.