A `198-cm` tall girl lies on a light (massless) board which is supported by two scales one under the top of her heal and one beneath the bottom of her feet. The two scales read respectively `36` and `30 kg`. What distance is the centre of gravity of this girl from the bottom of her feet? .

Options

A. `99cm`
B. `90cm`
C. `108cm`
D. `82cm`

Answer

C

Explanation

Let the required distance is `x`, then balancing the torque about centre of gravity
`(30g)x=(36g)(198-x)x=108cm`