Units And Measurement And Dimensions

The period of oscillation of a simple pendulum is given by $T = 2\pi \sqrt{\dfrac{l}{g}}$ where $l$ is about $80$ cm and is known to have $0.1$ cm accuracy. The period is about $1.5$ s. The time of $50$ oscillations is measured by a stop watch of least count $0.1$ s. The percentage error in $g$ is nearly