10+10 and 11+11 can give you the same answer.

Explain how?

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?

The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

Two in a corner, one in a room, zero in a house, but one in a shelter. What am I?

1 + 9 + 8 = ?
considering, 28 + 8 + 92 = 10

Find the missing number in the series below

13 -21 34 -55 ? -144

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

What month of the year has 28 days?

There is one four-digit whole number n, such that the last four digits of n2 are the original number n

What can go up a chimney down, but can't go down a chimney up?