Question

Each month, Kaisorn deposits $50.00 onto her public transportation card. It costs her $2.50 per trip to ride the subway. Thom deposits $40.00 on his public transportation card. It costs him $2.00 per trip to ride the subway.

If x represents the number of trips and y represents the amount remaining in each account, which system of equations represents their transportation costs?

50 − 2.5x = y
40 − 2x = y
50 + 2.5x = y
40 + 2x = y
50 − 2.5y = x
40 − 2y = x
50 + 2.5y = x
40 + 2y = x

Answer 1

50 − 2.5x = y
40 − 2x = y

Explanation: Kaisorn starts with $50 and spends $2.50 per trip, so y = 50 − 2.5x. Thom starts with $40 and spends $2.00 per trip, so y = 40 − 2x.