find force when baseball is hit

A baseball (m = 149 g) approaches a bat horizontally at a speed of 43.3 m/s (97 mi/h) and is hit straight back at a speed of 49.5 m/s (111 mi/h).

If the ball is in contact with the bat for a time of 1.10 ms, what is the average force exerted on the ball by the bat?

Neglect the weight of the ball, since it is so much less than the force of the bat. Choose the direction of the incoming ball as the positive direction.

i got 836.4N which is incorrect!

i first solved for J = m * vf - m * v0 which gives the answer in m/s

but then i used: J / chng time to find the avg. Force.

I think i'm getting confused because of the units.

please help.