Algebra

The formulas: Cgas = 5000 + 1100x, Csolar = 30 000 + 150x
model the total cost, in dollars, for electric and solar heating systems x years after installiation. What is the ratio of the total cost for electric heating to the total cost for solar heating 5 years after installation? What is this ratio 40 years after installation?

After 5 years:

Cgas = 5000 + 1100*5 = 10500
Csolar = 30000 + 150*5 = 30750

Ratio: 10500 / 30750 = 0,34

After 40 years:

Cgas = 5000 + 1100*40 = 49000
Csolar = 30000 + 150*40 = 36000

Ratio: 49000 / 36000 = 1,36