If "P" means "-", "Q" means "/", "R" means "+", and "S" means "*" then find the value of the following:

21 Q 7 R 9 S 10 P 13

If we add four times the age of John four years from now to five times his age five years from now we get ten times his current age.

How old will John be two years from now?

Solve below rebus puzzle?

I’m tall when I’m young, and I’m short when I’m old. What am I?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

Can you find the odd one out from the below words ?

First Second Third Forth Fifth Sixth Seventh, Eighth Nine Ten Eleven Twelve.

I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

Which is faster, Heat or Cold ? Explain.

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?