So after one month, FE (fitness explosion) costs $26 and Fitquest is $70; two months it's FE = $52, FQ = $85; three months it's FE = $78, FQ = $100; four months FE = $104, FQ = $115; five months FE = $130, FQ = $130. So answer C. 5 months is correct.
If he gets 20% commission and he sold $2580, multiply 2580 * .2 to get what he made
2580*.2 = $516
I'm assuming the funds earn 5% yearly?
Call x the amount he saves every year. The first year's deposit will be multiplied by 1.05 three times, the next will be multiplied by 1.05 twice, the third will be multiplied by 1.05 once, and the fourth will not generate interest (as it will immediately be used to buy the car).
Therefore, x(1.05^3+1.05^2+1.05+1)=21000, so 4.31x=21000. Dividing by 4.31, we see that x is approximately equal to 4872.
The answer is 492.126 :) Hope it helps!