Answer: 9mph and 18mph
Explanation:
T=D/R
If you take the distance, 81, and divide it by the rate of the cyclists combined, x+x-9 or 2x-9, you will get the time they meet at, 3 hours. To make this an equation. you would have
3=81/(2x-9)
If you solve this equation, x=18. This means one of the cyclists's rate is 18 mph, and the other, x-9, is 9 mph