Answer:
hope you understand the answers
First calculate the circumference. Usually this is the diameter times pi, but since we are told to estimate pi, the circumference equals 56 * 22/7 or 176 feet.
In 4 minutes, 4 * 60 = 240 seconds pass. In this time, a 20 second period will occur 240/20 = 12 times.
So we know that the rider rotates 12 times and each rotation takes them 176 feet, meaning that they will travel 12 * 176 = 2112 feet
Example: 
We can see that there is more than one number with the variable x, therefore, we say they're ''like terms'' and because of that they can be summed. We do this with all of the other numbers with similar variables. If no numbers with similar variables are left, like 4a, you don't do anything but write them as they are. You can also see that 8 and 9 can also be summed because neither of them has a variable, therefore they're similar.
In this step, you just do the operation with the numbers and keep the same variable.


since there are not more numbers similar in variables, this operation is done.

perimeter = 2L +2W
the problem states the length ( L) is 2 meters longer then width, so L = w+2
so perimeter =2(w+2) +2w
24 = 2(w+2) +2w
24 = 2w+4 +2w
24 = 4w+4
20=4w
w=20/4 = 5