The PSU charges $2 for a package weighing up to 3 lbs, plus an additional fee of $0.15 per lb over 3lbs. what is the most a package can weigh that you plan to mail if you have 3 dollars? (the nearest whole lb)

The correct answer is 9lbs!

You will start by subtracting the initial $2 which leaves you with $1 left. after that you count how many times $0.15 goes into your $1 left. That answer should be 6 time which is $0.90. Now you add the 6 to the original 3 to get 9lbs!