A kind heart person buy packed food at 3$/packet from United states and sells them at 1$/packet at Africa. After some time he becomes a millionaire.

How come the guy become millionaire ?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?

It's pretty hard to give up.
If you remove a part of it, you will be left with a bit.
Even if you remove another part, the bit still remains.
Remove one more and it still remains.

What is it?

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

Take one out and scratch my head, I am now black but once was red. What am I?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

What does this mathematical rebus means ?