What four weights can be used to balance from 1 to 30 pounds?

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

The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?

A boy collects white seashells from the sea and brings them home every night. When he has enough of them, he decides to sell them to a trader.

The trader is ready to buy the shells and he asks the boy about the quantity. At this, the boy starts calculating. He has a giant box that contains 3 mini boxes. Two of them have another mini box inside. If the giant box can hold 50 shells, how many brown shells can he sell to the trader?

While handling a project, the landscaper is asked by the owner of the mansion that he wants four trees in front of his mansion that are exactly equidistant from each other.

How will he do it?

Can you find out the missing number in the grid?

What is the fastest way to double your money?

Identify the movie name through below Rebus containing Pi Mouse and coconut tree..

Which tank will fill first?

Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?