Classic Puzzles-2
-
Upload
19ashish87 -
Category
Education
-
view
107 -
download
4
description
Set of 11 mind boggling concept based puzzles. It was part of puzzle competition organized by me at Institute of Rural Management, Anand
Transcript of Classic Puzzles-2
Puzzle a day keeps ‘RUSTING’ away
Round ‘A’
Numbers
1.Billly
• Billy is twice as old as Sally was, when Billy was as old as Sally is now. And the total of their ages is 28. How old are they?
2.a.How many Socks??
• Let's say that you have a drawer full of socks, 20 red socks (all identical) and 12 blue socks, and it is dark in the room. How many socks should you grab, to assure that you have at least one matching pair?
2.b.How many Socks??
• You have a draw containing 20 red socks, 12 blue socks, and 8 green socks. How many socks should you grab, to assure that you have at least one matching pair?
3.Confusion in Mixing….
• You have a cup of tea and a cup of coffee. You take one teaspoon of tea and mix it with your coffee and then you take one teaspoon of this mixture and mix it with the tea. Which cup contains more of its original contents?
4.Travelers and the Bread loaves
• One of them has five small loaves of bread, the second has three small loaves of bread. The third has no food, but has eight coins.
• He offers to pay for some bread. • They agree to share the eight loaves equally among the
three travellers, and the third traveller will pay eight coins for his share of the eight loaves.
• The second traveller (who had three loaves) suggests that he be paid three coins, and that the first traveller be paid five coins.
• The first traveller says that he should get more than five coins. Is he right? How should the money be divided up?
5.Play with Numbers
• I have in my mind any of the three digits 1, 2 or 3. You are allowed to ask me one question and you should come to know which digit i had in mind. The issue is i will answer only in form of Yes/No/Don’t know.
6.Kitne ka Katta hua?
• A person goes to a shopkeeper (SP)-1 and buys a pair of shoe for Rs.600 whose cost price was Rs.400.
• He gives SP-1 a note of Rs.1000. But the SP-1 didn’t had change. So, SP-1 goes to nearby SP-2, gets the change of Rs.1000 and return Rs.400 to customer.
• In the evening SP-2 comes back and says “The Rs.1000 note you gave in morning is fake. Return me my money”. SP-1 gives SP-2 Rs.1000 back.
• How much is the total loss for the SP-1in the whole transaction?
8.Dicey Dice
• You throw two dice on a table, add the numbers that turn up, and write their sum on a piece of paper.
• Pick up anyone dice without disturbing the other and add the number on the opposite face to the sum previously obtained.
• Throw this one die again and add the number that turns up to the last sum, obtaining a final sum.
• I will then turn around, pick up the dice, and reveal the final sum obtained.
9.Weight Conscious People
• Five people need to enter the lift and for that they need to know whether their total weight is less than 200 kg (since the lift's capacity is only 200 kg). However, no person is willing to let others know his own weight. Can they device a strategy with which each one of them will come to know the total weight of the group but nobody will know the weight of anybody else?
Imagination
10. 3*3 cube
• There was a black 3*3 cube. It was then painted with white color.
• How many cubes are there with
– 3 sides white
– 2 sides white
– 1 sides white
– 0 sides white
11.Out of Box
• A into 2 equal parts
• B into 3 equal parts
• C into 4 equal parts
• D into 5 equal parts
Solutions
1.Billy’s
• Let, Sally is S years old; Billy is B years old.
• Billy was once S years old. How long ago was that? – It was B-S years ago.
– How old was Sally then? She was S-(B-S) or 2S-B years old then.
• Billy is now twice that old: B = 2(2S-B) = 4S-2B or 3B = 4S. And we also know that S+B=28.
• We have two equations and two unknowns, we can probably solve for S and B.
• Sally is 12 and Billy is 16. By the way, I checked my work.
2.How many Socks??
A) if we take out 3 socks there has to be one pair of socks of either color.
B) Similarly, since there are 3 different color socks. So, in order to get atleast a pair, we must take out 4 socks out of the drawer.
3.Confusion in Mixing
• Let the volume of a cup is 100ml and volume of one teaspoon is 10ml.
• After iteration 1, – Volume of tea left in cup is 90ml. – Volume of coffee in coffee cup is 100ml and tea is 10ml.
• So, when 10ml of this mixture is taken out, it will have (10/11)*10 ml coffee and (1/11)*10ml tea (Using ratio method).
• When mixed with tea cup, the volume of tea in tea cup is 90+10/11ml=90.91ml tea and 100/11ml=9.09ml coffee.
• Whereas in case of coffee cup, coffee is 100-100/11ml = 90.91ml coffee and 9.09ml tea.
• The volume will always remain same.
4.Traveler and the Bread Loaves
• The first traveller is right; he should be paid more.
• Each man ended up with 2 and 2/3 loaves (eight loaves split three ways).
• So the second traveller (with three loaves) gave 1/3 loaf to the third traveller. The first traveller gave 2 and 1/3 (or 7/3) loaves to the third traveller.
• The first traveller gave seven times as much, and should get seven coins, with one coin going to the second traveller
5.Play with Numbers
• 1st is very simple and innovative. – You can directly tell me “ if the number in your mind is 1
then say Yes, if the number is 2 then say No else Don’t know”.
• 2nd is more authentic answer involving some skills. – You will say to me that “I have a number between 1.5 and
2.5 in my mind. Is your number less than my number?”.
– If i had 1 in my mind i will say yes. If i had 3 in my mind i will say no. If i had 2 in my mind, i will not be sure that what number between 1.5 -2.5 you have in mind, so i will say don’t know
6. Kitne ka Katta Hua?
• Solution Method 1: – We can visualize the question in scenes.
• Transaction 1 between SP-1 and customer • Transaction 2 between SP-1 and SP-2
– So, customer gave Rs.0 but took away Rs.400 shoes and Rs.400 cash. Total loss to SP-1 from customer Rs.800
– In transaction 2, SP-1 get Rs.1000 in the morning and returns Rs.1000 in the evening. So, there is no net loss or profit.
– Overall, from both transactions, total loss is Rs.800.
• Solution Method 2: – Write everything in +/- negative term with respect to SP1
• - Rs. 400 (shoes by customer) – Rs.400 cash (customer) + Rs.1000 (cash from SP-2) – Rs.1000 (cash to SP-2)
• Overall loss = Rs. 800
8.Dicey Dice Solution
• There is one feature in dice that we should know.
• There are six digits 1, 2, 3, 4, 5 and 6 whose total sum is 21 and there are three pairs of opposite faces. Therefore, in each pair of opposite face the sum of the digits are 7.
9.Weight Conscious People
• This is very innovative method to find average without revealing any information.
– 1st person will add ‘x’ to his weight and tell the sum to 2nd person. 2nd person will add his weight and tell the sum to 3rd person and so on. In this way 5th will get the sum of all 5 people and unknown ‘x’ which only 1st knew. First person will now subtract ‘x’ from the total and divide by 5 to get average.
– This way no one will come to know about other’s weight and can also board the lift.
10.3*3 cube
• 3 sides white – The one on the corners.
Total 8.
• 2 sides white – The one on the edges
except corner once. Total 12
• 1 sides white – The one on the centre of
the faces. Total 6
• 0 sides white – Core centre cube. Total 1
11.Out of box
• A into 2 equal parts
• B into 3 equal parts
• C into 4 equal parts
• D into 5 equal parts
