Planet and speff problem find mass

[physicsgurl12]

Homework Statement

The weigh tof spaceman speff, soley due to the gravitational pull of planet x at its surface is 389N. If he moves to a distance of 1.86*10^4km above the planets surface his weight changes to 24.31N. What is the mass of planet xif speffs mass is 75 kg.

Homework Equations

f=ma
f=gm1+m2/r^2

The Attempt at a Solution

i know the answers is 2.96*10^24 kg. nut idk how to get it

 

[SteamKing]

I would double check your second equation.

 

[physicsgurl12]

it m1*m2

 

[physicsgurl12]

what else?? I am still not getting it

 

[Redbelly98]

Use the F=G·m1·m2/r² equation, and plug in the given information. There are two sets of information, so you would get two equations:

(1) 389 N = G · __ · __ / __
(2) Use the other weight given in the problem to set up the second equation