388,753 views
25 votes
25 votes
Hi, can someone please help me with this? I know I’ve passed something like this before, but I can’t remember what to do.

Hi, can someone please help me with this? I know I’ve passed something like this before-example-1
User Monobono
by
2.8k points

1 Answer

30 votes
30 votes

Let's call x the maximum amount of miles Karissa can drive without the cost of the rental going over $40.

Then since they charge $18.95 plus $0.18 for each mile, Karissa will pay, in dollars:

18.95 + 0.18x

So, the maximum value of x is the one for which the above expression equals 40:

18.95 + 0.18x = 40

Now, to solve this equation, we can apply a sequence of operations on both sides of the equation, until we isolate the variable x and find its value:

18.95 + 0.18x = 40

18.95 + 0.18x - 18.95 = 40 - 18.95

0.18x = 21.05

0.18x/0.18 = 21.05/0.18

x ≅ 116.94

Now, rounding the answer to the nearest mile, we find 117 miles.

Therefore, Karissa can drive a maximum of 117 miles without the cost of the rental going over $40.

User Pteofil
by
3.0k points