Answer:
Friday: 300 dollars
Step-by-step explanation:
Let Omar's pay on Friday = x
Friday: Â Â x
Saturday: Â 1/4 x was spent.
Sunday: Â 2/3 *(x - (1/4)x ) = 2/3 * (3/4x) = (2*3/(3*4)x = (6/12)x = 1/2x
Dinner: Â 15 dollars
Remainder = 20% x = 20/100 x = 0.2x
x - (1/4x + 1/2(x) + 15) =  0.2x      Combine like terms on the left Â
x - (3/4x + 15) = 0.2x            Remove the brackets
x - (3/4)x - 15 =  0.2x            Combine like terms on the left
(1/4)x - 15 = 0.2x               Change 1/4 to a decimal
0.25x - 15 = 0.2x               Subtract 0.25x from both sides
0.25x - 0.25x - 15 = 0.2x - 0.25x  Combine
- 15 = - 0.05x                  Divide by - 0.05
-15 /-0.05 = - 0.05 x/ 0.05
300 = x