If eleven plus two equals one, what does nine plus five equal?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

Two boys were admitted to a school. When the headmaster asks them about their parents, they tell him that they have same parents (father and mother). On further inquiry, it turns out that they both share the same date for their birthday.

"Are you twins," ask the headmaster.
"No," replies the boys.

Is it possible?

Find the missing letter in the last circle logically in the given below picture.

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Can you complete the sequence puzzle?

AR TA GE CA LE VI LI _

Can you count the number of blocks in the picture below?

What came first, the chicken or the egg?

What are the 50th, 63rd and 100th numbers in the sequence below?
4, 5, 8, 8, 9, 9, 12, 13, 13, 13, 17, 18, ...