Answer: Heather paid $6187.5 for the car.
Explanation:
Mary bought a car for $9000 but sold it to Naomi at a loss of 75% after it was involved in an accident. This means that the price at which Naomi bought the car is Mary's cost of buying the car minus 75% of Mary's cost of buying the car. It becomes
9000 - (75/100 × 9000) = 9000 - 6750 = $2250
Naomi repaired the car and sold it to Heather for 175% more than she paid for it. This means that price that Heather paid will be the sum of Mary's cost of buying the car and 175% of Mary's cost of buying the car.
It becomes
2250 + (175/100 × 2250) = 2250 + 3937.5 = 6187.5