Error in the measurement of radius of the sphere is $2 \%$. The error in the calculated value of its volume is

A physical quantity A can be determined by measuring parameters $\mathrm{B}, \mathrm{C}, \mathrm{D}$ and E using the relation $A=\frac{B^a C^\beta}{D^\gamma E^\delta}$. If the maximum errors in the measurement are $\mathrm{b} \%, \mathrm{c} \%, \mathrm{~d} \%$ and $\mathrm{e} \%$ then maximum error in the value of A is

The density of a cube is measured by measuring its mass and length of its sides. The \% error in the measurement of mass and length are $5 \%$ and $6 \%$ respectively. The percentage error in the measurement of density is

A student measures time for 20 oscillations of a simple pendulum as $30 \mathrm{~s}, 32 \mathrm{~s}, 35 \mathrm{~s}$ and 35 s . If the minimum division in the measuring clock is 1 s , then correct mean time (in second) is