Acar detailing company charges $30 plus $18 per hour. another company charges $25 plus $20 per hour. how long is a job that costs the same no matter which company is used? (there should be a variable on both sides of the equal sign/equation)

The startup equation for this would be 30 + 18h = 25 + 20h. Subtract 20h from both sides to get 30 - 2h = 25. Now, you should subtract 30 from both sides. When you do, you get -2h = -5. Divide each side by -2 to isolate the h. h = 2.5. A job that costs the same no matter which company is used is 2.5 (2 1/2) hours long.

Well if you have 20 bats you probably want 20 balls? you don’t have enough context to answer the question.