Presentation College, Headford, Co Galway

PCH Puzzle Page!!

 

Test your numeracy ability with some basic puzzles!Scroll down for answers!

 

Q1. Divide 50 by 1/2 and add 20?!

 

Q2. A hurley and a sliotar cost £1.10. The hurley cost £1 more. How much does the sliotar cost?

 

Q3. If there are 327 apples and you take 42, how many do you have?!

Easy?!!! Scroll down for answers!

 

Q4. Complete the following steps

  • Pick any 3 digit number
  • Multiply by 7
  • Multiply by 11
  • Multiply by 13
    • Now scroll down and we will read your mind!!

 

Q5. Ten red socks and ten blue socks are all mixed up in a dresser drawer. The 20 socks are exactly alike except for their colour. The room is in pitch darkness and you want two matching socks. What is the smallest number of socks you must take out of the drawer in order to be certain that you have a pair that match?

 

Q6.A logician vacationing in the South Seas finds himself on an island inhabited by two proverbial tribes of liars and truth-tellers. Members of one tribe always tell the truth, members of the other always lie. He comes to a fork in a road and has to ask a native bystander which branch he should take to reach a village. He has no way of telling whether the native is a truth-teller or a liar. The logician thinks a moment, then asks one question only. From the reply he knows which road to take. What question does he ask?

 

Q7. Solution for question below will be posted at a later date!!

 

Q8.

Water lillies double in area every 24 hours. There is one water lily in the middle of a lake. If it takes 40 days for the lake to be completely covered in water lillies, on which day is it half covered?

Answers!!

 

Q1. 120

 

Q2. £0.05

 

Q3. 42 of course!!

 

Q4. Answer will be your 3 digit number wrote out twice (e.g. if you picked 134, answer will be 134134!!)

 

Q5. Solution: Three socks.

 

With two socks it is possible to have one red and one blue. But with three there is always a matching pair since either you will have chosen three of the same colour, or a matching pair and an odd one out.

 

Q6.

Solution: The challenge here is to find a question that forces a liar to lie about a lie and hence tell the truth.

This works: point at one of the forks and ask the native: “If I were to ask you if this road leads to the village, would you say yes?”

 

If the fork is the correct one, a liar would answer no to the direct question ‘does this road lead to the village?’ and thus his (lying) answer to the actual question must be yes.

 

The truth-teller will also answer yes if the road is the correct one.

 

Q7.

 

Awaiting solution

 

Q8.

 

39th Day!