SSC CGL Tier II 1 Dec 2016 Paper 1

(4) Remaining work $=1-\frac{2}{5}=\frac{3}{5}$parts
∵ (A + B) together do $\frac{3}{5}$th part of work in 6 days.
∴ Time taken by A and B in doing whole work =$\frac{6\times 5}{3}$ = 10 days
A does $\frac{2}{5}$th part of work in 9 days.
∴ Time taken by A in doing whole work $\frac{9\times 5}{2}=\frac{45}{2}$ days
∴ B’s 1 day’s work $=\frac{1}{10}-\frac{2}{45}$
$=\mathrm{}\frac{9-4}{90}=\frac{5}{90}=\frac{1}{18}$
$\therefore$ Required time $=18$ days