A truck can be rented from Company A for $110 a day plus $0.30 per mile. Company B charges $30 a day plus $0.40 per mile to rent the same truck. Find the number of miles in a day at which the rental costs for Company A and Company B are the same.

We know that Company B will be less expensive at first, but Company A will become a better option as the miles rack up. Eventually, Company A will be less expensive. There will be a point where the price will be the same for each company.

150 + .20x = Company A
70 + .40x = Company B

If we set these two equations equal to each other, we find out when the price will be the same.