Question

A sphere of mass 40 kg is attracted by another sphere of mass 80 kg by a force of 2.5*10^-6N. When their centres are 30mm apart, find G.

Answer 1

$g \times \frac{m1m2}{{r}^{2} } = f$
substituting given values
G=7.03*10^(-13)
which is not the correct value
I think the question is incorrect