Replace the question mark with the correct number.

Can you tell a 3D object that has just two surfaces?

Complete the table series riddle by finding the number that can replace "??".

John is looking at Jenifer, but Jenifer is looking at Jacob. John is married, but Jacob is not.

Is a married person looking at an unmarried person ?

Look at me. I can bring a smile to your face, A tear to your eye, Or even a thought to your mind. But, I can't be seen. What am I?

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

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

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

There is a square piece of paper with a hole that is denoted by the circle on the top right side in the given picture. You have to cut the paper in a manner that it forms two and only two separate pieces of paper and then rearrange the pieces in a manner that the holes come in the centre of the paper.

2, 3, 5, 9, 17, _ What is the next number in the sequence?