# Can you solve a riddle that even a computer can’t? In computer courses, sometimes a riddle is given that a person can solve, but not a single machine can solve yet. Here it is. ### How old are three sisters if:

Multiplying their ages gives the number 36. Adding their ages gives 13. The eldest is blonde. Multiplying their ages gives 36, which is one of the eight following combinations:

36 = 2 × 3 × 6, adding these numbers gives the number 11.

36 = 2 × 2 × 9, adding these numbers gives the number 13.

36 = 4 × 9 × 1, adding these numbers gives the number 14.

36 = 4 × 3 × 3, adding these numbers gives the number 10.

36 = 18 × 2 × 1, adding these digits gives 21.

36 = 12 × 3 × 1, adding these digits gives 16.

36 = 6 × 6 × 1, adding these digits gives 13.

36 = 36 × 1 × 1, adding these numbers gives the number 38.

There are two possible answers, since 2 + 2 + 9 is 13, and so is 6 + 6 + 1.

Note: “The eldest is blonde” – allows you to find out that there is the eldest daughter who does not have a twin. So, only the first formula suits us.

Solution: three sisters – the eldest of nine and two twins of two years. 