Sumit does 600 J of work in 10 min and Amit does 300 J of work in 20 min. Calculate the ratio of the powers delivered by them.

Given,

Work done by Sumit (W_S) = 600 J

Time taken by Sumit (t_S) = 10 min = 10 x 60 = 600 seconds

Work done by Amit (W_A) = 300 J

Time taken by Amit (t_A) = 20 min = 20 x 60 = 1200 seconds

Then,

Power delivered by Sumit (P_S) = $\frac{\text {Work done by Sumit}\ (\text W_\text S)}{\text {Time taken by Sumit}\ (\text t_\text S)} =\frac{600}{600} = 1\ \text W$

and

Power delivered by Amit (P_A) = $\frac{\text {Work done by Amit}\ (\text W_\text A)}{\text {Time taken by Amit}\ (\text t_\text A)} =\frac{300}{1200} = 0.25\ \text W$

So,

$\frac{\text P_\text S}{\text P_\text A}=\frac{1}{0.25} =4$