# Thread: Harry's Age

1. ## Harry's Age

Jack is twice as old as Harry. Harry is twice as old as Hannah.
Altogether, they are 63 years old. How old is Harry?

Jack = 2(2x)

Harry = 2x

Hannah = x

2(2x) + 2x + x = 63

Is this the correct equation set up?

2. ## Re: Harry's Age

Yes, that will lead you to the correct result if you solve for 2x, however we are being asked for Harry's age, and so I would set it up as follows:

Let:

$\displaystyle H$ = Harry's age, and then:

$\displaystyle 2H$ = Jack's age and

$\displaystyle \frac{H}{2}$ = Hannah's age.

Then, use the information regarding the sum of the ages:

$\displaystyle 2H+H+\frac{H}{2}=63$

Solving this equation will directly give us the quantity we are asked to compute.

Neither approach is necessarily superior to the other though. I simply tend to express things in terms of the quantity we seek, so that we explicitly solve for that variable to answer the question.

3. ## Re: Harry's Age

Oh to be 18 again!!

4. ## Re: Harry's Age

Originally Posted by Debsta
Oh to be 18 again!!
I was 18 years old in 1983. I concur. I would do anything to be 18 again, to go back to the year 1983. As I look in the mirror each day, I see a middle aged man trying to forget the reality that time has indeed rushed by since my teenage years. A sad reality we all must face on this planet---AGING.

5. ## Re: Harry's Age

Originally Posted by harpazo
I was 18 years old in 1983.
Quit complaining: I was 42 in 1983!

6. ## Re: Harry's Age

A sad reality we all must face on this planet---AGING.
Some don't get to face aging. Aging is much better than the alternative.

7. ## Re: Harry's Age

Originally Posted by Debsta
Some don't get to face aging. Aging is much better than the alternative.
I try to be positive but reality is a hard pill to swallow.

8. ## Re: Harry's Age

Originally Posted by MarkFL
Yes, that will lead you to the correct result if you solve for 2x, however we are being asked for Harry's age, and so I would set it up as follows:

Let:

$\displaystyle H$ = Harry's age, and then:

$\displaystyle 2H$ = Jack's age and

$\displaystyle \frac{H}{2}$ = Hannah's age.

Then, use the information regarding the sum of the ages:

$\displaystyle 2H+H+\frac{H}{2}=63$

Solving this equation will directly give us the quantity we are asked to compute.

Neither approach is necessarily superior to the other though. I simply tend to express things in terms of the quantity we seek, so that we explicitly solve for that variable to answer the question.

2H + H + H/2 = 63

3H + H/2 = 63

2[3H + (H/2)] = 63•2

6H + H = 126

7H = 126

H = 126/7

H = 18

Harry is 18 years old.