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

What has 88 keys?

The centre of the third figure is empty. What digit should fit inside?

I want to fill my bucket using both cold and hot water.
I have two taps for both cold and hot water. The hot water tap fills the bucket in exact 6 hours and the cold water tap fills the bucket in exact 4 hours.
I turn both of them simultaneously but I forgot to turn off another tap which removes the water out of the bucket. This tap can empty the bucket in 12 hours.

How Long will it take to fill the bucket?

Can you fill the blank with the correct number?

6 30 870 756030 _____

How do you go from 98 to 720 using just one letter?

What is both possible and impossible at the same time?

Why are all black people so quick ?

It belongs to you, but other people use it more than you do. What is it?

What do you get if you add 2 to 100 four times?