Why is this wrong THRUST? i showed work

[zcabral]

why is this wrong...THRUST?? i showed work!

Homework Statement

A rocket for use in deep space is to have the capability of boosting a total load (payload plus the rocket frame and engine) of 2.25 metric tons to a speed of 10 000 m/s.
If a different fuel and engine design could give an exhaust speed of 4600 m/s, what amount of fuel and oxidizer would be required for the same task?
metric tons

Homework Equations

vf=ve ln(mi/mf)

The Attempt at a Solution

10000=4600ln(x/2.25)
x= 19.71
but its wrong. can you help?

 

[D H]

The question asks for the amount of fuel and oxidizer, not the total mass of the vehicle.