fuel cost question

Question

using the information from the table a hybrid car uses gas at a cost in city $0.09 per mile and highway $0.08 per mile. during one week, the owner of a hybrid car drove 394 miles and spent $34.72 on gasoline. how many miles did the owner drive in the city? how many miles did the owner drive on the highway?

Answer 1

c+h =394

multiply both sides by .08

.09c +.08h =34.72

.08c +.08h = .08(394)

subtract to eliminate one variable

.01c = 34.72-31.52= 3.2

c = 3.2/.01 = 320 miles in the city

h=394-320 = 74 miles on the highway

check the answer

h=(34.72 -0.9c)/.08

h = (34.72-.09(320))/.08

=(34.72 -28.8)/.08

= 5.92/.08 = 74 miles on the highway