SSC GD 2021 PYQ — Question 66

The correct answer is option 1 i.e.  $\frac{19}{30}$

Efficiency = $\dfrac{Total work}{Time taken}$

Total work = LCM of 25 & 30 = 150

A's efficiency = $\dfrac{150}{25}$= 6 units/day

B's efficiency = $\dfrac{150}{30}$= 5 units/day

Total efficiency = 6 + 5 = 11 units/day

Total work done in 5 days = 11 × 5 = 55 units

Remaining work = 150 - 55 = 95 units

So the fraction of the work left = $\dfrac{95}{150}$= $\dfrac{19}{30}$