### Brain Teasers

# Last Time we Met

Said Alf to Bert, "The last time we met, our ages were both prime numbers, and when I was a quarter of the age I am now, you were that age plus half the age your father would have been thirty years previous to when he was six times the age you would have been when I was half your age". Said Bert to Alf "I'm off down the pub". How old were Alf and Bert the last time they met?

### Answer

Alf and Bert were 2 and 5 years old respectively the last time they met. If A and B are Alf and Bert's present ages and a and b are their ages when Alf was half Bert's age thenB - 3A/4 = (A/4) + (6b - 30)/2

Since their ages have always had the same difference we have

B - A = 3b - 15 = b - a

and since 2a = b then a = 3 and b = 6. So their ages differ by 3. Since all primes except 2 are odd and differ by an even number we can only have 2 and 5, Bert being the older of the two. The father plays no part in the problem!

Hide Answer Show Answer

## What Next?

View a Similar Brain Teaser...

If you become a registered user you can vote on this brain teaser, keep track of which ones you have seen, and even make your own.

### Solve a Puzzle

Comments hidden to avoid spoilers.

## Follow Braingle!