SSC CGL 2023 PYQ — Question 72

The correct answer is option 3 i.e. $2\frac{52}{73}$.

Let the total work to be done LCM(6, 9, 11) be 198 units.

Total work = Efficiency × Time

Efficiency of A = $198 \over 6$ = 33 units/day

Efficiency of B = $198 \over 9$ = 22 units/day

Effciency of C = $198 \over 11$ = 18 units/day

Efficiency of A, B and C together = 33 + 22 + 18 = 73 units/day

Total time taken by A, B and C together to complete the work = $198 \over 73$ = $2\frac{52}{73}$

Hence the total time taken by A, B and C together is $2\frac{52}{73}$.