Why is 6 afraid of 7?

How many triangles are there on the puzzle below?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

It is deaf, Dumb and Blind!!!

Still, always tells the truth. What is it?

Solve the mathematical equation in the picture below.

Prove that twice of ten is the same as twice of eleven.

How many sides does a circle have?

A deaf and mute man goes to the train station. Tickets for the train are 50 cents each. The man goes to the ticket booth and hands the man inside just a dollar. The man in the booth hands him two tickets.

How did the man in the booth know to give him two tickets without even looking at him?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

A Japanese ship is sailing in the Indian Ocean. The captain of the ship feels tired and decides to take shower to be rejuvenated. He goes to take the shower after keeping his diamond-studded Rolex watch and gold chain on the table.
When he comes back after 15 minutes, he finds them missing. There are 4 crew members on the ship and he calls them one by one to ask them what they were doing in that duration.

Following are the answers:
1. Crew 'A' who is the cook replies that he was cooking mutton for the crew members.
2. Crew 'B' who is a housekeeper tells that he was sleeping in his room.
3. Crew 'C' who is the engineer says that he was checking on the generator.
4. Crew 'D' who is another housekeeper says that he was correcting the hoisted flag that was put upside down.

It took only a couple of seconds for the captain to find the thief. Can you find the thief too?