My puzzles are all too easy

A woman says to her doctor, 'It just ocurred to me that if yousquare my daughter's age, the result would equal twice her current age'.

The doctor replies, 'tell your daughter happy birthday for me'.

How old is the daughter? 2 solutions.

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Let the daughter's age be X.

Thus, 2 * X = X * X.

The obvious solution is X = 2, but X = 0 also works. (Happy birthday

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The doctor cannot deduce this from her remark - it must be something she already knew.

0, or 2, exactly.

0 is more likely - it would explain how the doctor knows that this is the girl's birthday, if she has just been present at the birth. Though it makes the mother's remark somewhat surprising - she has another year to express this rather inane thought, and might have more pressing concerns on the day of her delivery.

Hi!

He-he... read on!

So when 'exactly' is her birthday?

Cheers!

- Risto -

One of these solutions is correct, but the other is wrong. Hint: age has a dimension.

George Weinberg posed:

and Nick Wedd anwered:

to which George Weinberg replied:

If age has a dimension, then it sure seems like the only possible answer is zero.

For example, if the daughter's age were 2 years, the square of her age would be four square-years and twice her age would be four years. Any other dimension would give the same inequality, unless the age is zero.

Bob H

That's easy - It was her birthday on the day the doctor wished happy birthday!

Nope. 0 years != 0 years^2.

Nope. Just because the value is zero doesn't mean that the dimensions don't matter.

Otherwise 0 Hz = 0 s = 0 ohm = 0 mho and other troublesome things.

However, I'd posit that age is scalar, it's the ratio of two periods (that of someones life-length, and that of a year).