algebra
posted by Gemma .
Mandi can be paid in one of two ways: Plan A A salary of $400 per month, plus a commission of 8% gross sales; or Plan B A salary of $610 per month, plus a commission of 5% of gross sales. For what amount of gross sales should Mandi select Plan A?
I have no idea how to write an inequality for this. It would help if you could give me the inequality for this and walk me through it a little.
Thank you!

let s be the amount of sales in $
Pay(planA) = 400 + .08s
Pay(planB) = 640 + .05s
This question is very similar to the one you just posted.
Solve the two right sides of the above equations.
That will tell you for what amount of sales the pay would be the same.
So above that value, one of the plans would be better, for below that value it would be the other.
I will let you decide which would be the better. 
Thank you for your help!