What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

Which tank will fill first?

No one wants to have it, but if one got it, he does not want to lose it. What is It?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

Move four matchsticks to the below square to form three squares?

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!!!

Dwayne Johnson was running away with the loot from a heist in his car along with Vin Diesel. One tire was punctured and he dropped down to replace it. While changing the wheel, he dropped the four nuts that were holding the wheel and they fell into a drain. Vin Diesel gave him an idea using which they were able to drive till the rendezvous point.

What was the idea ?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?