Hi,

I have the following problem, does anybody know how to solve it?

A man is x years old and the year is x^2.
He dies 1971, when is he born?

I.e.
x = present age
x^2 = present year
1971 = the year he dies

When is he born?

Well, simply look for the closest square number smaller than 1971. Then the square root of that + (1971 - year) is what you're looking for.

I'm not sure what you mean..

MISSTAKE:

It should be 1871 NOT 1971!!

Btw, I have the answer for x but I don't know how to solve the problem as a whole.

So, x = 43 and x^2 is therefore 1849

And as I said it's 1871

...
...
Try this:
In the year 1849, the person was 43 years of age.
1849 - 43 = YearOfBirth

.

Thanks but this doesn't help, because the x is actually unknown!
I.e. I only know the x because it says so in the key.

But IF i don't have the key, how do I SOLVE?

The problem again:

A man finds out that the present year is the his present age raised to the second power. This man dies in 1871, but when is he born?

x = age
x^2 = year
Dies in 1871
When is he born?

Defunkt provided the key to the solution.

Since the person died in 1871, he was born BEFORE 1871.

Suppose the person was 35 years of age in the year 1225 (=35^2)
That means he was six hundred some years old when he died.
Probably not the case.

Try x=40
40^2 = 1600. DOB: 1600 - 40 = 1560; death 1871; age 311
x=41
41^2 = 1681. DOB: 1681 - 41 = 1640; death 1871; age 231
x=42
42^2 = 1764. DOB: 1764 - 42 = 1722; death 1871; age 149
x=43
43^2 = 1849. DOB: 1849 - 43 = 1806; death 1871; age 65
x=44
44^2 = 1936. DOB: 1936 - 44 = 1892; death 1871; age -21 (that's a negative 21)

Does that help?

.

Aha, by trying! That helps very much - thanks!