The car is traveling at 40 miles per hour (mph) and the distance it has traveled is 81 miles. You can use the distance equation, which is d = rt, where d stands for distance, r stands for rate of travel/speed, and t stands for time.
In this case, you will substitute in your known values and solve for the variable you don't know:
d = rt
81 = 40t
To find out how long it takes for the car to travel 81 miles at a rate of 40mph, you will need to solve for the variable (t), which stands for time.
