Teaser Of The Day No. 143

[Carl]

Read the little poem and answer its question if you can.

The number of girls who do wear a watch
is double the number who don't.
But the number of boys who do not wear a watch
is double the number who do.

If I tell you the number of girls in my class
is double the number of boys,
Can you tell me the number I teach ?

Here's a clue: More than 20; below 32 !


Answer will be provided next Thursday evening after 21:00.

[Carl]

ANSWER

27.

Solution:

The number of boys must be a multiple of 3 (3, 6, 9...) so that it can be split in the ratio of 2:1 (no watch:watch).

The number of girls is double the no. of boys (6, 12, 18...)

So the totals can only be 9, 18, 27...