The fuel efficiency rating for a car is 28 mi/gal hghwy, 20 mi/gal cty. one week=220 mi using 9 gal. how much fuel was used for city driving ? How many miles were driven on the highway?
2006-10-09 12:46:54 · 4 answers · asked by kc m 1 in Education & Reference ➔ Homework Help
Two equations
Using the gas consumed as variables
220 m = 28 H + 20 C
H + C =9
220 = 28 H + 20 (9 - H)
220 = 28 H = 180 -20H
40 = 8H
5 gallons on the highway
4 gallons city
140 miles highway
80 miles city
j
2006-10-09 12:55:35 · answer #1 · answered by odu83 7 · 0⤊ 0⤋
You have two unknowns, the number of miles driven in city C, and on highway H. The number of gallons used driving in the city is C/20, on the highway is H/28. The sum is 9 gal. Your second equation is C+H=220mi. Replace C in the first equation with (220-H). Solve it.
2006-10-09 20:00:31 · answer #2 · answered by Anonymous · 0⤊ 0⤋
4 gallons for city driving, and 140 miles on the highway
2006-10-09 19:53:35 · answer #3 · answered by usnavybrat07 2 · 0⤊ 0⤋
let x = miles at 28mpg, let y = miles at 20mpg so x+y =9 is milage equation, 28x +20y = 220 is second equation of your linear system
2006-10-09 19:56:34 · answer #4 · answered by dla68 4 · 0⤊ 0⤋