A college student has set aside $240 for the rest of the school year to use the coin-operated laundry facility in his dormitory. Each time he uses the machines, it costs $7.50. Choose the equation that represents the amount remaining in his fund, f, after he has done laundry x times. Find the amount remaining in the fund after 12 trips to the laundry facility.
+86 The equation should be f - 7.5x
when f = fund and x = trips
When we substitute in the known values for f and x, the problem looks like this: 240 - 7.5(12)
First multiply: 7.5*12 = 90
Then subtract: 240 - 90 = 150
After 12 trips to the laundry, the student will have $150 left in his fund.
