math challenge

Week of September 16 - 22, 1996

Dodos for Donald

Karen and Donald are trying to join an exclusive club for dodo-bird watchers (Order of the Extinct Aviaries). Donald will be allowed to join if he can find a 2-digit number that is divisible by both 15 and 45, and which is 10 less than the number Karen has to find.

Karen has to find the smallest possible 3-digit number. She does so with only a moment's thought.

Five minutes later, Donald is still agonizing over his number. Maybe this is just the club's way of saying he doesn't make the grade.

What number should Donald find? Is there any hope he will be allowed to join?

See the solutions