UGC NET CSE | June 2023 | Part 1: 17

Question

If $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ can complete a piece of work in $3,5$ and $6$ days respectively, they together will complete the work in

• A. $1 \frac{3}{7}$ days
• B. $2 \frac{4}{7}$ days
• C. $1 \frac{1}{2}$ days
• D. $2 \frac{1}{3}$ days

Answer 1

Per day work done by A – 1/3
Per day work done by B – 1/5

Per day work done by C – 1/6

Now, suppose A, B , C together would take x days to complete the work.
Then, per day work done by A,B and C together = (1/3 + 1/5 + 1/6) = 1/x

Solving for x – 1/x = (10+6+5)/(6*5)
x = 30/21 = 10/7 = 1 3/7 days.

 

Ans : Option A.