Time period of a simple pendulum is given by T=2 π ( )/(g) where is...

Time period of a simple pendulum is given by $\mathrm{T}=2 \pi \sqrt{\frac{\ell}{g}}$ where $\ell$ is the length of pendulum and g is acceleration due to gravity. If percentage increase in the length and acceleration due to gravity are $69 \%$ and $21 \%$ respectively then find out percentage increase in time period.