1 mile = 5280 feet
81 * 5280 = 427680 feet per hour
1 hour = 3600 seconds
427680 / 3600 = 118.8 feet per second
118.8 * 15 = 1782 feet in 15 seconds
The amount of feet the car would have travelled in 15 seconds is;
1782 ft
Speed of the Car = 81 mph
We are given that;
1 mile = 5280 ft
Thus; 81 miles = 81 × 5280 = 427680 ft
Thus; Speed of car is now 427680 ft/hr
Now, we know that;
3600 seconds = 1 hour
Thus, the speed is;
427680 ft per 3600 seconds.
To find how many ft the car will travel in 15 seconds, we use use proportion to get;
(427680 × 15)/3600 = 1782 ft
Read more at; https://brainly.com/question/11637115
