A rectangular field of 18 ft × 10 ft is carpeted, and the price of carpet is $ x per square yard. Please use the formula with X to express the total price of carpet. (Hint: 1 yard = 3 feet)

1 yard = 3 feet, so 1 square yard = 9 square feet.

18× 10 = 180 square feet = 20 square yards

So the total price is 20x.