Jay gave $35 to his brother. Jack's mother gave him another $25. The amount of money Jack had in the end was four times as much as the amount of money Jay. How much money did each of them have at first?
let x = amount of money each had at first
x - 35 = amount Jay had in the end
x + 25 = among Jack had in the end
x + 25 = 4 (x - 35)
x + 25 = 4x - 140
x - 4x = -140 - 25
-3x = -165
x = -165/-3
x = $55