Joseph is going on a trip and he needs to rent a car. He looks online and finds two companies that offer different pricing options for car rentals. Company A charges $0.25 per mile plus a $50 rental fee. Company B charges $0.45 per mile plus a $20 rental fee.

To determine the maximum number of miles that Joseph can drive for Company B to be a better buy, we need to compare the costs of each company for different mileage amounts.

For Company A, the cost can be calculated using the equation: Cost = (0.25 * miles) + 50
For Company B, the cost can be calculated using the equation: Cost = (0.45 * miles) + 20

We want to find the point at which the cost for Company B is equal to or less than the cost for Company A. Let's set up the equation:

(0.45 * miles) + 20 <= (0.25 * miles) + 50

Simplifying the equation:

0.45 * miles - 0.25 * miles <= 50 - 20

0.20 * miles <= 30

Dividing both sides of the equation by 0.20:

miles <= 150

Therefore, the maximum number of miles Joseph can drive for Company B to be a better buy is 150 miles. So the answer is C) 150 miles.