Percentage Error Questions

A physical quantity $P$ is related to four observations $a$, $b$, $c$ and $d$ as follows:
$$P=a^3{b}^2/c\sqrt{d}$$
The percentage errors of measurement in $a$, $b$, $c$ and $d$ are $1\%$, $3\%$, $2\%$ and $4\%$ respectively. The percentage error in the quantity $P$ is: