Transform the word THINK into BRAIN while changing only one letter at a time in a manner that each of the word in the process is a real word!!!

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

Find out a multi-digit number that if multiplied by the number 9 or any of its multiplications products (i.e. 18, 27, 36, 45,..) will result in the multiplication factor repeated (n) number of times.

A boy and a girl are sitting on the porch.
"I'm a boy," says the child with black hair.
"I'm a girl," says the child with red hair.
If at least one of them is lying, who is which?

If we tell you that there is a relation between the numbers and letters in the given figure, can you analyze it and find the missing letter in the last box?

What jumps when it walks and sits when it stands?

There are forty elephants and they have forty-fore heads. How can this be possible?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?

When can we add 2 to 11 and get 1 as the correct answer?

An equation has been laid down using a few matchsticks. However, as you can see, the equation is not correct. Can you correct the equation if you are allowed to add or remove 5 matchsticks?