RRB NTPC Mains or Stage 2 Model Paper 6 with solutions

(b) Ratio of times taken by A and B = 100 : 130= 10 : 13.
Suppose B takes x days to do the work.Then, 10 : 13 : : 23 : x
$\Rightarrow \mathit{x}=\left[\frac{23\times 13}{10}\right]\Rightarrow \mathit{x}\frac{299}{10}$.
A’s 1 day’s work =$\frac{1}{23}$ ;B’s 1 days work
=$\frac{10}{299}$.
(A + B)’s 1 day’s work
$=\left[\frac{1}{23}+\frac{10}{299}\right]=\frac{23}{299}=\frac{1}{13}$
∴A and B together can complete the job in 13 days