Perplexing problems 1.
What’s the number?
It has 3 digits
It is a multiple of 11
All the digits are odd
The sum of its digits is a square number
Answer: 979
Perplexing problems 2.
How many go by bus?
 In a school of 1200 pupils, 580 are girls.
 One third of the pupils travel to school by
bus
 462 boys do not go by bus
 How many girls do go by bus?
Answer: 242
Perplexing problems 3.
How many altogether?
 Sam and Ben collect marbles
 Sam tells Ben, “If you give me 5 marbles I’ll
have twice as many as you.”
 Ben says, “If you give me 4 we would have the
same number”.
 How many marbles were there altogether?
Answer: 54
Perplexing problems 4.
What number was the middle house?
 Five houses next door to each other were on
the odd side of the road.
 They were all 2-digit numbers, and in ascending
order
 The fourth one was the only prime number
 What number was the middle house?
Answer: 95
Perplexing problems 5.
How much altogether?
 Ann, Bob and Carol are counting their money
 Ann and Bob together have £5.98
 Bob and Carol together have £6.47
 Ann and Carol together have £8.51
 How much do they have altogether?
Answer: £10.48