Let x=bob’s original amount of money
Let 9x=Bessy’s original amount of money
9x+4=5(x+4)
9x+4=5x+20
4x=16
x=4
9(4)=36
Bob had $4 before earning $4 and Bessy had $36 before earning $4
-x + 2y = -1....when x = 15...so we sub in 15 for x and find y
-15 + 2y = -1
2y = -1 + 15
2y = 14
y = 14/2
y = 7 <==
We can display this as an algebraic equation:
x * 1.25 = 40
Now divide by 1.25
x = 40/1.25
x = 32
Hope this helps!
