Answer:
Each of them had $49 at first.
Step-by-step explanation:
Given:
Cedric and Doug each had an equal amount of money.
Let the number of money they had at first be x
Cedric spent = $35
Doug spent = $28
Cedric Money left = 
Doug Money left = 
the ratio of Cedric money to Doug money was 2:3
Hence the expression can be made as;

Now by cross multiplication method we get;

Now we will use distributive property to elaborate the same;

Combining common terms we get;

Using Subtraction property we get;

Hence $49 they each had at first.
Look at it this way:
g=2
H=7
so it would be 2*5-7*3
than just do the multiplication first so 2*5=10 and 7*3=21 than subtract the two 10-21=-11
C. Plumber A and Plumber B will both charge $135 if they each work 2.5 h.
Multiply the first equation by 3, and multiply the second equation by 4.