Solution: Let x be the total cost.
Let y be the cost for the discount card.
Let z be the number of daily bus passes.
According to the question
Total cost = Cost for the discount card + 1.50 Number of daily bus passes
⟹x = y + 1.50 z ────── ①
It is given in the question that
Total cost = $29.50
Number of daily bus passes = 15
Substituting the above value in equation ①, we get
29.50 = y + 1.50(15)
29.50 = y + 22.50
29.50 – 22.50 = y
y = $7
Hence, Paul spends $7 on the student discount card.
Paul bought a student discount card for the bus. The card allows him to buy daily bus passes for $1.50. After one month, Paul bought 15 passes and spent a total of $29.50. He spends $7 on the student discount card.