if mass of earth decreases by 25% and its radius increases by 50% , then acceleration due to gravity at its surface decreases by nearly

ans:67%

how?

Question

if mass of earth decreases by 25% and its radius increases by
50% , then acceleration due to gravity at its surface decreases by
nearly
ans:67%
how?

Abhay Kumar · Accepted Answer

g=GM/r2
g' = G*3M/4 / (3r/2)2
= 0 33 g
decrease = g-0 33g = 0 67 g