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

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

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

By using all numbers, i.e. 123456789 and subtraction/addition, operators number 100 can be formed in many ways.
Example: 98 + 7 + 6 - 5 - 4 - 3 + 2 - 1 = 100

But if we add a condition use of the number 32 is a must. Then there are limited solutions.
One of such solution is: 9 - 8 + 76 + 54 - 32 + 1 = 100

Can you tell me any other solution?

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

What is the next number in this series?

4,12,84,3612....

You’re out on the water and see a boat filled with people. You look away for a second and look back again, but this time you don’t see a single person on the boat. Why? Hint: The boat did not sink.

What is next number in the pattern below:

131 517 192 123 ?

The more of this there is, the less you see. What is it?

A B C D E F G H

These are the letters given to you. Now you have to find out the letter that comes two to the right of the letter which is immediately to the left of the letter that comes three to the right of the letter that comes midway between the letter two to the left of the letter C and the letter immediately to the right of the letter F.