#12 Factorial factory
Set by Mary Ellis
Mathematicians write 9! to represent the number 鈥�9 factorial鈥�, which means 9 脳 8 脳 7 脳 6 脳 5 脳 4 脳 3 脳 2 脳 1 = 362,880.
How many zeros will 10! end with?
How many zeros will 25! have at the end? (Careful, the answer isn鈥檛 five.)
How many zeros will 1066! finish with?
Solution next week
#11 Club shuffling
Solution
If the players are A, B, C and D then the possible games are: AB vs CD, AC vs BD and AD vs BC. So there are three games in total.
If A wins all their games then all the left-hand teams are winners, so B, C and D each win once and lose twice. If A loses all their games, the reverse is true: B, C and D each win twice and lose once.
If there are two teams of three players, a similar process shows that there will be 10 games altogether. If one person wins all their games then each other player will win four. If one person loses all their games then each other person will win six.
Quick quiz #244
set by Bethan Ackerley
1 What is the world's largest living snail species?
2 Which figure from Greek mythology lends their name to the element with atomic number 73?
3 What name is given to the stages that immature arthropods go through between moults?
4 Galantamine is used in treating symptoms of which condition?
5 What was the first artificial nuclear reactor?
Quick quiz #244
Answers
1 The Australian trumpet (Syrinx aruanus)
2 Tantalus (also known as Atys) 鈥� the element is called tantalum
3 Instars
4 Alzheimer's disease
5 Chicago Pile-1