The formula for the amount of car with principal value of P, annual rate r simple intrest and time t is,
[tex]A=P+\frac{P\cdot r\cdot t}{100}[/tex]Determine the amount of Fiat and Mercedes-Benz.
[tex]\begin{gathered} A_F=55000+\frac{55000\cdot8\cdot3}{100} \\ =55000+13200 \\ =68200 \end{gathered}[/tex]For Mercedes-Benz, time of 36 months is equal to 3 year.
[tex]\begin{gathered} A_M=55000+\frac{55000\cdot4.8\cdot3}{100} \\ =55000+7920 \\ =62920 \end{gathered}[/tex]The formula for the amount in compounr intrest is,
[tex]A=P(1+\frac{r}{100})^t[/tex]Determine the amount for cars Lexus and Audi.
24 months is equivalne to 2 years.
[tex]\begin{gathered} A_L=55000(1+\frac{10}{100})^2 \\ =55000(1.1)^2 \\ =66550 \end{gathered}[/tex]For Audi, 48 months is equaivalent to 4 years.
[tex]\begin{gathered} A_A=55000\cdot(1+\frac{4}{100})^4 \\ =55000\cdot(1.04)^4 \\ =64342.22 \end{gathered}[/tex]So the minimum amount is $62920. Thus cheapest car is Mercedes-Benz.