That's correct, but again there is an equation to be found and solved :)

There are two points in time, now and then.

We define $$x$$ as Jimmy's age now.
"Then" is when Tom was $$x$$ years old.

| Person | Now | Then |
| ----- | ----- | ----- |
| Tom | 24 | x |
| Jimmy | x | |

To get from now to then (reading Tom's line) we subtract 24 and add x, hence the bottom right cell is $$x-24+x = 2x-24$$.


| Person | Now | Then |
| ----- | ----- | ----- |
| Tom | 24 | x |
| Jimmy | x | 2x-24 |

Now the equation is simply $$2 \times (2x - 24) = 24$$, or $$x = 18$$.


Jimmy was 12 when Tom was as old as Jimmy is now.

Thus, Jimmy is 18 now, because 6 years ago Jimmy was 12 and Tom was 18.

I did guess and check again, haha.


SimpleStacker

I was as old as 18 when I was Jimmy's age.

noknees

Since it was solved so quickly, here's the most difficult one in the set (it was marked as difficult, and not mandatory), which made 

How old is Jimmy? Tom is 24 years old. He is twice as old as Jimmy was when Tom was as old as Jimmy is now.

science

Secondary school math puzzle

Scroogey

Since it was solved so quickly, here's the most difficult one in the set (it was marked as difficult, and not mandatory), which made **me** fetch pen and paper:

> How old is Jimmy? Tom is 24 years old. He is twice as old as Jimmy was when Tom was as old as Jimmy is now.
