Answer:
[tex]Highway = 155\ miles[/tex]
[tex]City = 130\ miles[/tex]
Step-by-step explanation:
Given
[tex]Highway = 31mi/gallon[/tex]
[tex]City = 26mi/gallon[/tex]
[tex]Total\ Miles = 285[/tex]
[tex]Total\ Gallons = 10[/tex]
Required
Determine the number of miles driven on the highway and on the city
Represent the gallons used on highway with h and on city with c.
So, we have:
[tex]c + h = 10[/tex] ---- gallons used
and
[tex]31h + 26c = 285[/tex] --- distance travelled
In the first equation, make c the subject
[tex]c = 10 - h[/tex]
Substitute 10 - h for c in the second equation
[tex]31h + 26c = 285[/tex]
[tex]31h + 26(10 - h) = 285[/tex]
Open bracket
[tex]31h + 260 - 26h = 285[/tex]
Collect like terms
[tex]31h - 26h = 285 - 260[/tex]
[tex]5h = 25[/tex]
Make h the subject
[tex]h = \frac{25}{5}[/tex]
[tex]h = 5[/tex]
Substitute 5 for h in [tex]c = 10 - h[/tex]
[tex]c = 10 - 5[/tex]
[tex]c = 5[/tex]
If on the highway, he travels 31 miles per gallon, then his distance on the highway is:
[tex]Highway = 31 * 5[/tex]
[tex]Highway = 155\ miles[/tex]
If in the highway, he travels 26 miles per gallon, then his distance on the highway is:
[tex]City = 26 * 5[/tex]
[tex]City = 130\ miles[/tex]