Wednesday, 15 April 2015
When I saw the now famous Cheryl's Birthday problem, it reminded me of this one. It's a few years old (the woman might have been Cheryl's grandmother), but has stood the test of time:
A travelling salesman rings a doorbell; woman answers.
Salesman: Good morning, madam. I'm selling children's books. Do you have any children and what ages are they?
Woman: I have three. The product of their ages is 36.
Salesman: I can't work out their ages from that; tell me more.
Woman: The sum of their ages equals the number of the house next door.
Salesman [who can see whether the houses go up in odds/evens or up one side and down the other, but doesn't know which side next door she means]: I still can't work out the ages.
Woman: The eldest plays the piano.
Salesman: Now I can work out their ages.
So what are the ages of the three children?