Finding Ratios of Forces in a Two-Force System | Homework Question

[Nivlac2425]

Homework Statement

Here's the question:
Two forces, Fa and Fb, are applied to an object. The larger force is Fa. When both forces point due east, the object's acceleration has a magnitude of 0.50 m/s^2. However, when Fa points due east, and Fb points due west, the acceleration has a magnitude of 0.40 m/s^2. Find the ratio of Fa/Fb of the magnitudes of the forces.

Homework Equations

F = ma ?
d = Vt + 1/2at^2 ?

The Attempt at a Solution

I've tried manipulating the F = ma equation to no avail. Maybe it has something to do with d = Vt + 1/2at^2 but I think maybe I'd have to use Fa + Fb = sigmaF.
But to be honest, I have no idea where to start, especially with finding ratios. I just need a little help forward. Thanks

 

[rl.bhat]

Fa + Fb = ma1...(1)
Fa - Fb = ma2...(2)
take the ratio of 1 and 2 and solve for Fa and Fb

 

[Nivlac2425]

I've tried something like that, but the book says that the answer is 9. Does that change anything?

 

[Nivlac2425]

Nevermind my last post, I've gotten the answer to be 9. Thanks! I'll know how to do ratios now