Prize Puzzle Competition 19

Closing date is 30th October 1999

55. The other day I was asked if I could help someone by providing change for a 50p piece. (I think they wanted to make a phone call.)
When I emptied out my pockets I found I had 13 coins which totalled 4.99
But I was unable to give change for the exact value of 50p!

How many 50p coins did I have?

56. If the only sister of your mother's only brother had an only child,
what would be its relationship to you?

57. The diagram shows the cross-section of a circular tunnel of diameter 3 metres, designed to carry a single line of traffic. The road AB is 2 metres wide.
A lorry is shown fitted exactly into the tunnel so that it touches at its top corners. (This can only happen in puzzles!) The lorry is 1.2 metres wide across its top.

What is the height from the road to the top of the lorry?

The winner of Competition #18 was Jennie Foster of Tiffin Girls School, Kingston upon Thames.
The answers were:

52.The Ace was in position 3. (The only possible arrangements were QKAJ and QJAK)
53.Nelson was born on a Friday. (The Gregorian calendar had been corrected in line with today's rules in 1752.)
54. My friend was 49. (It was required to find the two sets of numbers 5, 10, 49 and 7 ,7, 50; both totalling 64. And then, since the children were not twins, it must have been the first set.)