Rahul use addition property of equality in step 2.
Solution:
The image of the question is attached below.
Step 1:
combine like terms together.
To make the denominator same multiply and divide 2x by 5.
Step 2:
By addition property of equality, add 
on both side of the equation.
Step 3:
Step 4:
Multiply by 
on both side of the equation.
Hence Rahul use addition property of equality in step 2.
We'll take 1.25 miles as one minute (x) and take 100 as total distance (D) while T is the time it took to reach that distance.
T = D/x
putting the values in
T = 100/1.25
T = 80
80 minutes is the answer.
1. Use Difference of squares: a^2-b^2=(a+b)(a-b)
(x+k)(x-k)=0
2. Solve for x and k
x=+-k
k=+-x
C, E, and F have 50 50 chance
