Solution:

Just form an equilateral triangle, planting trees at the vertices. Now find the center of the triangle and plant the fourth three on that point. In this manner you will form a shape of tetrahedron and all the trees will have equal distance between each other.

Solution:

If you look into the picture, you can see the cut lines. If the four people cut along with the lines, each one of them will have 1/5th of the cake.

Solution:

The first figure tells you where you have to make the cut in the paper. Now you have two pieces of paper. If you rotate the right piece to 180 degrees, you will get what is shown in the figure two. Now the hole is in the center of the paper.

Solution:

The Pink servant is the truthful one.

In order to prove the same, let us take all of them one by one assuming that the selected one is telling the truth. This is because all of them are disagreeing with each other which means that three servants are lying while one is telling the truth.

Assume that the Orange servant is the truthful one. Under this condition, the orange one is having either 6 or 8 legs. And each of the other octopus is lying will then have 7 legs. Under this condition, the total number of legs will be 6 + 7 + 7 + 7 = 27 legs or 8 + 7 + 7 + 7 = 29 legs. But the Orange servant said that they have 28 legs all together. Thus he is lying.

Now if we simply follow the same logic with all other servants as well, we will come up to the conclusion that only the Pink servant is truthful.

Solution:

If we take the worst case, she will have to take out 12 + 1 = 13 candies.

Solution:

Let us solve this problem with variables to find the general nature. Let us assume that there are x black chocolates and y white chocolates. Three things can happen when you take out two chocolates.
1) You take out two black chocolates.
Then, you will be replacing one black chocolate and so the jar will have x+1 black chocolates and y-2 white chocolates.
2) You take out two white chocolates.
Then, you will be replacing 1 black chocolate and so the jar will have x-1 black chocolates and y white chocolates.
3) You take out 1 black chocolate and 1 white chocolate. Then, you will be replacing a white chocolate and so the jar will have x-1 black chocolates and y white chocolates.
Thus at every step, you are wither removing a black chocolate or replacing two white chocolates by one black chocolate irreversibly till there is just one chocolate left. Therefore each white chocolate is equivalent to two black chocolates.

This, if the number of white chocolates are odd in number, the last one remaining will be white chocolate and if the number of white chocolates are even in number, the last one remaining will be black chocolate.

Solution:

Suzie took the 100 toffees from the largest tin and then she kept one of the smaller tin of toffees inside the empty tin. In this manner, when her sister checked, there were still 100 toffees in each of the tins.

Solution:

The smart answer would have been 'I will be quite glad and will take a day off from office to celebrate the happiness with my husband.'

The nature of question is hypothetical and you can answer in the same manner too. Usually the unmarried girls will be shocked at such a question but if you are smart, you can pull it off smartly.

Solution:

The correct answer to this twisted problem is four times.

You can try solving the problem with the help of two coins and if you are unable to understand, you may even disassemble some clockwork to find out.

Now to explain it, it is evident that the small one will turn 3 times against the big one. The reason is because it has 8 teeth which is 1/3 of the big one (24). But now we want the big wheel to stop and the small one to turn around the big one. In this process, the small one will make an additional turn on its way around the big one. This makes a total of four turns.

Solution:

The answer is simple. The trains will be at same distance from Point P when they meet speaking on approximation. However, the train A will be closer to the point P by its own length if we are not taking meeting of train as perfectly overlapping.