How many two-digit numbers are multiples of 3 and also factors of 81?

3x=9
so try x=1,2,3,4 and see.

I have been given a riddle that has driven me mad ... but worse, once given the answer. I just became baffled. Can anyone please explain why 487 is the answer to this riddle.

i have 15 cherries, 42 cherries
& a cherry. you have 25 cherries.
Lets swap cherries.
Cherry Christmas.

How many cherries?

I hope you can now see why i'm baffled at this answer.

If this is a puzzle you got from the Great Big British Quiz it's probably baloney, and there's no intelligent reason for that answer.