SOLUTION: Hi, Ive been given a question. "Twelve years ago Jack was five times as old as Jill. In three years time Jill will be half of Jack's age. What are Jack and Jill's present ages?"
Algebra ->
Customizable Word Problem Solvers
-> Age
-> SOLUTION: Hi, Ive been given a question. "Twelve years ago Jack was five times as old as Jill. In three years time Jill will be half of Jack's age. What are Jack and Jill's present ages?"
Log On
Question 322312: Hi, Ive been given a question. "Twelve years ago Jack was five times as old as Jill. In three years time Jill will be half of Jack's age. What are Jack and Jill's present ages?"
I've tried heaps of different equations with no luck so far.
If Jack = y and Jill = x I have been using the following -
y = 5x - 12
x = y/x + 3
So I go x = (5x - 12)/x + 3
I've tried several others I just can't figure it out. Becoming really frustrating and a push in the right direction would be hugely helpful! :)
Thanks! Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! "Twelve years ago Jack was five times as old as Jill. In three years time Jill will be half of Jack's age. What are Jack and Jill's present ages?"
..
let Jill's age be x now
Let Jack's age be y now
..
12 years ago their ages were
Jill x-12
Jack y-12
..
y-12=5(x-12)
y-12=5x-60
y-5x=-48.......... equation 1
..
after 3 years their ages will be
Jill x+3
Jack y+3
(x+3)= 1/2 (y+3)
2(x+3)=y+3
2x+6=y+3
2x-y=-3......... equation 2
..
Add equation 1&2
y-5x+2x-y=-48-3
-3x=-51
x= 17 which is Jill's age now
Plug the value of x in equation1
y-85=-48
y=37 Jack's age now
