Name a key which is hardest to turn.

What occurs twice in a week, once in a year but never in a day?

I am dry when I go inside, but wet when I am pulled outside.
The longer I am inside, the stronger I get
When I am completely out, I am wet and I literally sag
Who am I?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

A mother bought three dress for her triplets daughters(one for each) and put the dresses in the dark. One by one the girls come and pick a dress.
What is the probability that no girl will choose her own dress?

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

There is a box. The area of its top is 240 square units, the area of the front is 300 square units and the area of the end is 180 square units.

Can you calculate the dimensions of this box with the given data?

When can we add 2 to 11 and get 1 as the correct answer?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?