The equation would be 4y=5x 4(x+15)=5x x+15=y
let x be the amount that Shelia deposits each time
let y represent the amount that Sherri deposits each time
4(x+15)=5x
4x+60=5x
-4x -4x
60=x
Check:
x+15=y 60+15=y y=75
4(75)=5(60)
300=300
Shelia deposits $60 each time.