Let d be the distance of a point from the earth where gravitational forces on the rocket due to the sun and the earth become equal and opposite.
Then distance of rocket from the sun = (r−d).
if m is the mass of rocket, then
GMsm(r−d)2=GMEmd2 or (r−d)2d2=MSME or r−dd=√MSME
Given, MS=2×1030kg,ME=6×1024kg,
r=1.5×1011m
∴r−dd=√2×10306×1024=103√3
or rd−1=103√3 or rd=1+103√3=√3+103√3
d=r√3√3+103=1.5×1011×√3√3+103
d=2.6×108m