What is the distance between the Moon and Earth if the mass of the Moon is 7.34 X 10^22kg, and the force of attraction between the two is 2.00 X 10^20 N?

- the answer is 3.83 X 10^8 kg.

I just want to know how to get there

If masses of Earth and moon are M1 and M2 (kg), and r is distance in meters

Force between them is G M1 M2/r^2

Where G is the Gravitation Constant, approx = 6.673 10^-11 (N m^2 Kg^-2)

I hope you find the above helpful.

Well there's some problem here, you're looking for a distance, but you say the answer is in kilograms?

You need to have another look.