SOLUTION: Jack is twice as old as Jill, but in five years time he will only be one and a half times as old. How old are Jack and Jill now?

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Question 1152323: Jack is twice as old as Jill, but in five years time he will only be one and a half times as old. How old are Jack and Jill now?
Found 2 solutions by MathLover1, MathTherapy:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

let Jack's age be x and Jill's age y
if Jack is twice as old as Jill, we have
x=2y........eq.1
if in five years time he will only be one and a half times as old, we have
x%2B5=1.5%28y%2B5%29
x=1.5y%2B1.5%2A5-5%29
x=1.5y%2B7.5-5%29
x=1.5y%2B2.5%29........eq.2
from eq.1 and eq.2 we have
2y=1.5y%2B2.5
2y-1.5y=2.5
0.5y=2.5
y=2.5%2F0.5
y=5
go to eq.1
x=2y........eq.1, substitute y
x=2%2A5
x=10
Jack is 10 years old now and Jill is 5 years old now


Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!

Jack is twice as old as Jill, but in five years time he will only be one and a half times as old. How old are Jack and Jill now?
You don't have to make this a COMPLEX solution by creating 2 separate variables. So, proceed as follows:

Let Jill's age be J

Then Jack's is 2J

We then get: 2J + 5 = 1.5(J + 5)

2J + 5 = 1.5J + 7.5

2J - 1.5J = 7.5 - 5

.5J = 2.5

Jill's age, or highlight_green%28matrix%281%2C5%2C+J%2C+%22=%22%2C+2.5%2F.5%2C+%22=%22%2C+5%29%29

You should now be able to find Jack's age!