Andrew M. answered 09/21/17
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
Hi Shawn:
We need to set up a cost function in terms
of number of months.
Letting m= number of months:
cost = 20m + 100
we want that to total $400 so
20m + 100 = 400
subtract 100 from both sides
20m = 300
divide both sides by 20
m = 300/20 = 15 months
Questions?