Question

if mass of planet is 10 % less then that of the earth and radius of the planet is 20 % greater then that of earth then the weight of 40 kg person on that planet

Answer 1

g on the planet = {G*(9/10 M)}/ R^2
g=(6.67x 10^ -11)(5.4 x 10^24) / (4/5 x 6400)^2
g= 25 kg.

Answer 2

Weight of 40 kg person on planet is 25 kg

Given:

Mass of the planet is 10% less that the earth.

Radius of the planet is 20% greater that earth.  

To Find:

Weight of 40 kg person on the planet.

Solution:

Gravity is directly proportional to mass  

Gravity is indirectly proportional to square of radius

Where mass is 10% less and radius is 20% greater that earth

Then the gravity of the planet becomes 0.625

Weight of 40 kg person on planet = 40 $\times$ 0.625

Weight of 40 kg person on planet = 25 kg