Raymond B. answered 12/14/22
Math, microeconomics or criminal justice
4 years ago Jack was twice Jay's age
x-4 = 2(y-4) = 2y-8
x-2y =-8+4 = -4
x-2y =-4
multiply both sides by 4
4x-8y = -16
save this 1st equation to subtract from the next 2nd equation
in 4 years Jack will be 1 1/4 times Jay's age
x+4 = (5/4)(y+4)
4x+16 = 5y +20
4x-5y = 4 is the 2nd equation
4x-8y = -16 is the 1st equation
subtract 1st from 2nd to eliminate one variable
4x-5y - (4x-8y) = 4-(-16)
4x-5y-4x+8y = 4+16
8y-5y =20
3y = 20
y =20/3 = 6 2/3 years old for Jay now
x=2y-4= 13 1/3 - 4= 9 1/3 years old for Jack now
check the answers
4 years ago they were 2 2/3 and 5 1/3
5 1/3 is twice 2 2/3
16/3 = 2(8/3)
in 4 years they will be 10 2/3 and 13 1/3
13 1/3 is 1 1/4 times 10 2/3 = (5/4)(32/3) = 40/3 = 13 1/3