RRB Non Technical Model Papers 6 with solutions

(2) (A+B)'s 1 hour's work
$\frac{1}{9+\frac{36}{60}}$=$\frac{\frac{1}{48}}{5}=\frac{5}{48}$hours
C's 1 hour's work $=\frac{1}{48}$
(A+B+C)'s 1 hour's work
$\frac{5}{48}+\frac{1}{48}=\frac{1}{8}$  ...........(1)
A's 1 hour's work = (B+C)'s 1 hour's work.........(2)
From equation (1) and (2)
2 × A's 1 hour's work $=\frac{1}{8}$
A's 1 hour's work $=\frac{1}{16}$
B's 1 hour's work $=\frac{5}{48}-\frac{1}{16}=\frac{1}{24}$
Therefore, B will finish the work alone in 24 hours.