SSC CHSL Model Paper 5

X ’s one day’s work = $\frac{1}{25}$th part of wholework.
Y ’s one day’s work = $\frac{1}{30}$th part of whole work.
Their one day’s work = $\frac{1}{25}+\frac{1}{30}=\frac{1}{150}$th
part of whole work.
Now, work is done in 5 days $\frac{11}{150}\times 5=\frac{11}{30}$th of whole work
∴ Remaining work $=1-\frac{11}{30}=\frac{19}{30}$th of whole work
Now, $\frac{1}{30}$th work is done by Y in one day.
∴ $\frac{19}{30}$th work is done by Y in $\frac{1}{\frac{1}{30}}\times \frac{19}{30}=19$ days