Trucks can be rented from Company A for ​$90 a day and ​$0.30 per mile. Company B has ​$30 a day and ​$0.70 per mile. Find the # of miles in a day when the rental costs for the companies are equal.

Answer 1

Let x be the number of miles in a day

A: y=90+.30x

B: y=30+.70x

To figure out the number of miles where they are equal, set the equations equal to each other. (This is actually solving using the substitution method)

90+.30x=30+.70x Subtract 30 from both sides

90+.30x-30=30+.70x-30 Simplify

60+.30x=.70x Subtract .30x from both sides

60+.30x-.30x=.70x=.30x Simplify

60=.40x Divide both sides by .40

60/.40=.40x/.40 Simplify

x=150 miles