The moon orbits the earth with an orbit radius and period 27 days

PHYSICS · Subjective · CBSE · Physics · Gravitation · Gravitation

Problem

The moon orbits the earth with an orbit radius

3.8 \times 10^5 \text{ km}

and period 27 days. The radius of the earth is

6.4 \times 10^3 \text{ km}

. From this information deduce the density of the earth.