Teasers

Suppose you draw 10 gloves and they happen to be all white. Now, you draw out 6 gloves and they all happen to be black in colour but of the same hand. Now, you need to draw one more glove to ensure that you get a black glove of the other hand and hence, a black pair of gloves. Hence, you need to draw 17 gloves in total.

If in any direction the bear is facing south, then the bear should be at the north pole. In northern polar region, only polar bears exist, which are white in colour.

Dingo belongs to the dog family. The rest of the animals belong to the cat family.

As the farmer has a mango tree, he can sell mangoes and not guavas as guavas do not grow on mango trees. Hence, the number of guavas he can sell is 0.

In the worst case scenario, the first two socks that the boy picks can be of different colours, i.e. one white and  one black.  Now, the 3^rd sock that he picks will be either white or black that will pair with one of the 1^st two socks. Hence upon drawing 3 socks, he will get a pair.

It is impossible to have a triangle with lengths of sides as given for triangle 2. Hence, triangle 1 has a bigger area.

Penguins live in the Antarctic (south), not the Arctic (north).

Time taken by the 2 mother ships to meet each other =  90/ (50 + 40) = 1 hour
Distance travelled by the shuttle boat in this 1 hour = 70 nautical miles
Fuel consumed by this boat = 0.5 x 70 barrels = 35 barrels

These numbers are nothing but the squares of 4, 5, 6 and 7 written with their digits in the reverse order. Hence, the next number will be 8² = 64 with the order of its digits reversed, i.e. 46.

The entire system can be imagined as the ice floating in water without the stone and the stone in a massless invisible boat floating on the water.
(I) When the ice is floating on water, it displaces a volume of water the mass of which is equal to its own mass. When the ice melts, it becomes liquid water. Upon melting, mass does not change. Hence, volume of this water must be equal to the volume, which was being displaced when it was in form of ice.
(II) As soon as the ice melts, the masless boat vanishes. When the stone was floating in this boat, a volume of water was being displaced the mass of which was equal to that of the stone (as the boat was massless). As the boat vanishes, the stone sinks. When the stone sinks in water, it is displacing a volume of  water, which is equal to its own volume. But because of the fact that it sinks, the mass of this volume of water has to be lesser than that of the stone. This implies that the volume of this water displaced by the stone is less than the volume of water displaced when it was floating. So, the water level comes down.
By combining the results of both the cases, the water level will decrease. 

You first get 75 chocolates for Rs. 75. Then you exchange the 75 wrappers of these 75 chocolates for 25 chocolates. You keep wrapper of 1 chocolate with you and exchange the 24 wrappers for 8 chocolates. Now you have 9 wrappers with you (8 + 1 you saved before) which you exchange for 3 chocolates. Now, you exchange wrappers of these 3 chocolates for 1 more chocolate. Hence, the total number of chocolates you end up getting is 75 + 25 +  8 + 3 + 1 = 112
 

When the boat with the stones was floating in water, a volume of water was being displaced the mass of which was equal to the combined mass of the boat, the man and the stones. When the stones are thrown in water, the boat is displacing a volume of water; the mass of which is equal to that of the combined mass of the man and the boat. Clearly, this volume is less than what was being displaced before. Now, when the stones are thrown in water, they displace a volume of water equal to their own volume. Because of the fact that they sink in the water, the mass of this volume of water must be less than their masses. But when they were floating in the boat, a volume of water had to be displaced the mass of which was equal to that of the stones. Clearly, the volume of water displaced when the stones were in the boat was more than when it is empty. Hence, the water level comes down.

The train is electric. Therefore, there would be no smoke.

The hat is red. If Timothy doesn't know his hat colour, then the other two men's hats cannot be both blue otherwise he would know his hat is red. When Imran doesn't know his hat colour either, that means Jatin's hat could not be blue otherwise Imran would have to know his hat was red to fulfill the information discovered through Timothy's answer.

You draw 17 gloves and suppose they all happen to be black of one hand. Then you draw another 15 gloves and suppose they all happen to be white of 1 hand. Now, you need to draw just 1 more glove, which will pair with a white or a black you have drawn before. Hence, you need to draw 17 + 16 + 1, i.e. 33 gloves to ensure that you get a pair.

Number of red socks = 18
Minimum number of socks to be drawn to ensure that atleast two of them are blue = 18 + 2 = 20

Even before it was discovered, Mount Everest was the highest peak in the world.

The length of the side asked for will be maximum if the other side (6 units) is perpendicular to either of the 2 parallel sides. In this case, its length becomes 10 units. This side will be the shortest if the other 2 parallel sides are as close to each other as is feasible. In this case, the length of the side has to be greater than (20 - 12 - 6)  2 units.

Take 6 balls and keep 3 each in each pan. Now, if 1 of these balls is the heavier one, select the 3 balls of which one is the heavier one. Take 2 balls out of these 3 and keep them in the balance, 1 in each pan. If these 2 are of equal mass, then the 3^rd ball you left out is the heavier one. Else, the heavier ball out of the 2 is the heavier ball you wanted.  Suppose all the 6 balls you picked were of equal mass. Then 1 out of the 3 balls you left out is the heavier one. Now, as before, you can identify the heavier ball by doing just 1 weighing.  Hence, the number of weighings you have to do is just 2.

When the boat was floating in water, it was displacing a volume of water, the mass of which was equal to that of the boat. When the boat sinks, it displaces a volume of water the mass of which must be lesser than that of the boat. Hence, the 2^nd volume of water displaced must be less than the 1^st. So, the water level would come down.

As you pass the vehicle in 3^rd place, you are now in 3^rd place. Hence, there are two vehicles ahead of you.

For the 1^st 10 checkpoints, he has to give 30 coconuts, 1 out of each bag. Having crossed the 10^th checkpoint, he is left with 90 - 30, i.e. 60 coconuts with 20 in each bag. He empties out contents of 1 bag, puts 10 coconuts each in the other 2 bags and leaves the 3^rd empty bag behind. He now has 60 coconuts in 2 bags with 30 each. He now crosses another 15 checkpoints, giving 2 coconuts at each point. Having crossed the 25^th checkpoint, he is left with 60 - 30, i.e. 30 coconuts with 15 in each bag. He empties the contents of 1 bag into the other and leaves the empty bag behind. He now has 1 bag with 30 coconuts. He now crosses the last 5 checkpoints giving 1 coconut at each. Having crossed the 30^th and the last checkpoint, he is left with 30 - 5 = 25 coconuts.

The shortest distance possible would be from the corner of the floor to the midpoint of the other vertical edge of the adjacent wall to the corner of the ceiling. If you open the 2 walls along this edge, the path travelled by the ant becomes the diagonal of a rectangle with its length equal to 20 ft and breadth = 10 ft and the diagonal is the shortest possible distance between 2 opposite vertices of a rectangle. Length of this diagonal is 10 x 5^0.5 which is choice 3.

The tide raises both the water and the boat. So, the water will never reach the fifth rung.

The series is nⁿ - n. Putting n = 4, we get 252.

A and B go across. A stays and B comes back. Time spent = 4 minutes
C and D go across. Time spent = 10 minutes
Total time spent = 14 minutes
Now A goes across and gets B.
Time spent = 3 minutes 
Total time spent = 17 minutes

At the circumcentre as the circumcentre is equidistant from all the 3 vertices.

In the worst case scenario: the first 2 socks that the man picks can be of different colours, i.e. one brown and one black. Now, the 3^rd sock that he picks will be either be brown or a black that will pair with one of the 1^st two socks. Hence, upon drawing 3 socks, he will get a pair.

Sylvester is living in the Southern hemisphere. Except for USA, all the other countries are in the southern hemisphere. Hence, Sylvester could not possibly living in USA.

The answer is 14.
You drop the first plastic ball from the 14^th floor. If it breaks, then you can determine the highest floor by dropping the plastic ball no more than 13 times (drop it from the 1^st floor, and if it doesn't break, drop it from the 2^nd floor, and if it still doesn't break, drop from the 3^rd, etc).
If the first ball survives the drop from the 14^th floor, you then drop it from the 27^th floor (14 + 13 = 27). If it breaks, you can complete your test in no more than 12 drops with the second ball by dropping it between the floors 15 to 26.
If from the 27^th floor, the first ball still doesn't break, the next floor to drop it from is the 39^th (14 + 13 + 12 = 39). If it breaks, drop the second ball from floors 28 to 38 (max 11 drops).
Repeat the experiment the same way whenever the first ball doesn't break; after the 39^th floor should be the 50^th floor (14 + 13 + 12 + 11), then the 60^th floor (14 + 13 + 12 + 11 + 10), and so on. If the first ball survives 11 drops, you will be on the 99^th floor. In that case, it only takes one more drop to complete the whole test.