physics an exotic finish ...how do i solve this?

Question

an exotic finish to massive stars is that a neutron star, which might have as much as five times the mass of our Sun packed into a sphere about 10 km in radius! Estimate the surface gravity on this monster.

answer: 6.7 x 10^12 m/s^2

is this one similar as the above in terms of solving it?

2. A typical white dwarf star, which once was an average star like our Sun but is now in the last stage of its evolution, is the size of our Moon but has the mass of our Sun. What is the surface gravity on this star?

answer 4.4 x 10^7 m/s^2

Answer 1

My constants may slightly differ from yours:
The gravitational constant G = 6.674x10^-11 (m^3/(kg*s^2))
The mass of our Sun: M = 1.989×10^30 kg
The radius of our moon: r = 1.737x10^6 m

1. The surface gravity on this monster is:
G*5M/(10^4)^2 = 6.674x10^-11*9.945×10^30/10^8
= 6.637x10^12 (m/s^2)

2. The surface gravity on this typical white dwarf star is:
G*M/r^2
Please do the math.