How much was spent

Question

Paul bought a student discount card for the bus. The card allows him to buy daily bus passes for $1.50. After a month, Paul bought 15 passes and spent a total of $29.50. How much did he spend on the student discount card?

Answer 1

Total $29.50 includes spending 15 times $1.50 times $1.50, i.e. $22.50.  So the rest of the money spent, $7, must have been the cost of the student discount card.

 

It would be interesting to know how much each daily bus pass would cost, if Paul had no discount card. Then we'd be able to determine if the purchase of the discount card made economic sense (overall savings).