Find the amount of work done against gravity in moving a 150kg rocket

[sdfsfasdfasf]

Homework Statement

Find the amount of work done against gravity in moving a 150kg rocket from the surface of the Earth to 18000 km above the center of the Earth.

Relevant Equations

E = -Gmm/r

I started by calculating the energy at the Earths surface, which is just -G(150)(6 x 10^24)/(6400 x 10^3) = -0.9 x 10^10, and calculating the energy at the orbit radius, E = -G(150)(6 x 10^24)/(18000 x 10^3) = -3.4 x 10^9, then doing some subtraction we have -3.4 x 10^9 - (-0.9 x 10^10) = 5600 x 10^6 J. The answer provided in my textbook is 6 x 10^5 J which is clearly not what I got. Any tips?

 

[Orodruin]

Any tips?

Get a better textbook?

 

[nasu]

Possible typo in the textbook. The answers section.

 

[sdfsfasdfasf]

So my answer is correct?

 

[kuruman]

So my answer is correct?

Yes.