49 pumps can empty a reservoir in 61/2 days, working 8 hours a day. If 196 pumps are used for 5 hours each day, then the same work will be complete in ?

Answer: Option C

Let the required number of days be x
Then,
More pumps, Less days (Indirect proportion)
Less working hour/day, More days (Indirect proportion)
$$\begin{array}{c}\text{Pumps 196}:49\text{hfill}\\ \text{Working hour/day 5}:8\text{hfill}\end{array}\}::\frac{13}{2}:x$$
$$\begin{array}{rl}& \therefore 196\times 5\times x=49\times 8\times \frac{13}{2}\\ & \iff x=\left(49\times 8\times \frac{13}{2}\times \frac{1}{196\times 5}\right)\\ & \iff x=\frac{13}{5}\\ & \iff x=2\frac{3}{5}\end{array}$$