Question

A man does $200\text{J}$ of work in $10$ seconds and a boy does $100\text{J}$ of work in $4$ seconds.
Find the ratio of the power delivered by the man to that of power delivered by the boy.

• A. $4:3$
• B. $3:4$
• C. $4:5$
• D. $5:4$

Answer 1

The correct option is C $4:5$

Power delivered by the man is
$P_{man}=\frac{200\text{J}}{10\text{s}}=20\text{W},$
and that by the boy is
$P_{boy}=\frac{100\text{J}}{4\text{s}}=25\text{W},$
The ratio is
$\frac{P_{man}}{P_{boy}}=\frac{20}{25}=\frac{4}{5}$