[Guest]

A boy and his big sister are sitting around the kitchen table

chatting.

“You know, Sis, if I took away two years from my age and gave them

to you, you’d be twice my age, huh!”

“Well, why don’t you just give me one more on top of that? Then

I’ll be three times your age.”

So just how old is each sibling?

[Guest]

  Reveal hidden contents

they are both 6 years old.

6-2=4 and 6+2=8 and 8 is twice as much as 4.

6-3=3 and 6+3=9 and 9 is thrice as much as 3.

And those are some pretty smart 6 year olds.

[Guest]

  ChuckJerry said:

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they are both 6 years old.

6-2=4 and 6+2=8 and 8 is twice as much as 4.

6-3=3 and 6+3=9 and 9 is thrice as much as 3.

And those are some pretty smart 6 year olds.

Yep

[Guest]

  Reveal hidden contents

Using algebra we can do it so ...

2(x - 2) = x + 2

2x - 4 = x + 2

x = 6

[Guest]

  Ben Law said:

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Using algebra we can do it so ...

2(x - 2) = x + 2

2x - 4 = x + 2

x = 6

  Reveal hidden contents

only because they happen to be the same age. Really you should set up a system that says

2(x-2)=y+2

and

3(x-3)=y+3

solve for y (y=2x-6 using the top equation) and substitute (3x-9=2x-6+3 in the bottom equation) and then x=6. so does y.

[unreality]

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2(x-2) = y+2

2x-4 = y+2

2x = y+6

3(x-3) = y+3

3x-9 = y+3

3x-6 = y+6

thus:

2x = 3x-6

0 = x-6

x=6

and then from there you get y=6 also

they are both 6 years old

[Guest]

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They are each 6 years old:

6 - 2=4, 6 + 2 = 8, 4 x 2 = 8.

4 - 1 = 3, 8 + 1 = 9, 3 x 3 = 9. Simple.

If it says it's his big sister, then how can they be the same age, you did a typo.

Edited July 9, 2008 by SillouhetteMind

[Guest]

  SillouhetteMind said:

If it says it's his big sister, then how can they be the same age, you did a typo.

  Reveal hidden contents

They are each 6 years old:

6 - 2=4, 6 + 2 = 8, 4 x 2 = 8.

4 - 1 = 3, 8 + 1 = 9, 3 x 3 = 9. Simple.

It could be just a trick to through you off. It could refer to the physical size, or the simple fact she was born a few seconds before him.

[Guest]

  SillouhetteMind said:

If it says it's his big sister, then how can they be the same age, you did a typo.

  Reveal hidden contents

They are each 6 years old:

6 - 2=4, 6 + 2 = 8, 4 x 2 = 8.

4 - 1 = 3, 8 + 1 = 9, 3 x 3 = 9. Simple.

I suspect that, having found out that they are the same age, we assume them to be twins (of which the sister was born first)

Either that or 6 years ago their parents had a baby girl and were quick try for another!

[Guest]

The girl was just born seconds before