Find the Next Number in the Sequence

2 9 3 1 8 4 3 6 5 7 ?

Solve the mathematical equation in the picture below.

A bridge is about to collapse. There are four people P, Q, R and S on one of the sides. Before the bridge collapses, they want to cross it. Now since the bridge is too weak, it can only stand the weight of two people at a time. Also, it is night time and nothing is visible. They have just one torch with them.

Now P takes one minute to cross the bridge, Q takes two minutes to cross, R takes five minutes to cross and S takes ten minutes to cross.

The bridge will collapse in seventeen minutes. How will they be able to cross the bridge before it collapses?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

What are the next two letters in the following series and why?
W A T N T L I T F S _ _

*Hint: Check Puzzle Title

What Adam and Eve do not have but the rest of the people have?

There are forty elephants and they have forty-fore heads. How can this be possible?

The current time can be represented by below textual rebus.

0
=========
B.Sc
LLB

Can you tell us the current time?

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

I have eight fingers and two thumbs but I do not live. What Am I?