Answer: Simplified expression- 
Step-by-step explanation: You get the product by simplifying it.
I tried my best, I hope this it what you were looking for:)
If a wheel makes a full turn, it will have traveled the entire distance around that wheel. After 3 revolutions, it should have traveled 3 times its circumfrence.
The circumfrence of a circle is equal to the diameter times pi. (about 3.14)
21 × 3.14 = 65.94 = circumfrence = 1 revolution
3 revolutions = = 65.94 × 3 = D. 197.82 in.
We need to use the following formula of distance .
Distance= speed * time .
For the first time
distance = 6r
And let the average rate for the second time be s
So distance = 5s
Since distance remains same, so we get
6r=5s
Now we have to solve for s. And for that we need to get rid of 5, by dividing both sides by 5, that is

And that's the required average rate for the second trip .
0.10
1/10
Hope I helped!
Let me know if you need anything else!
<span>~ Zoe</span>