How can you take 2 from 5 and leave 4?

Find the next number in the series?
2, 12, 36, 80, 150, 252, 392, _ ?

Name a key which is hardest to turn.

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

With the help clues provided in the image, can you find the 5 digit key?

John and Jill are madly in love with each other. To remind Jill of his pure love, John wants to send her a ring by post but in their country where burglary is quite prominent, any package that is not locked comes under the risk of being stolen for the contents.

John and Jill possess many padlocks but neither one of them has the other key.

Can you find a way John can send the ring to Jill safely?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

Solve the equation in the image by looking at the pattern closely.

A farmer went to a market and bought a wolf, a goat, and a cabbage. On his way home, the farmer came to the bank of a river and rented a boat. But crossing the river by boat, the farmer could carry only himself and a single one of his purchases: the wolf, the goat, or the cabbage. If left unattended together, the wolf would eat the goat, or the goat would eat the cabbage. The farmer’s challenge was to carry himself and his purchases to the far bank of the river, leaving each purchase intact. How did he do it?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?