math algebra mille per day

Question

A truck can be rented from Company A for ​$70 a day plus ​$0.20 per mile. Company B charges ​$40 a day plus ​$0.30 per mile to rent the same truck. How many miles must be driven in a day to make the rental cost for Company A a better deal than Company​ B's?

For Company A to have a better​ deal, the truck must be driven more than ... miles per day.

Answer 1

Stone, you probably know how to do the math once you’ve translated the problem from English to math.

First, give a name to each quantity:

Let m be the miles per day at the break even point.

Now, write equations for each relationship that we know of:

What is the cost of renting from A?

costA = 70 + .20 * m

What is the cost of renting from B?

costB = 40 + .30 * m

What do we want to know? We want the value of m that makes costA = costB.

70 + .2*m = 40 + .3*m

So solve this for m

Then, For Company A to have a better​ deal, the truck must be driven more than m miles per day