Can you solve the below tricky visual equation?

I know a 5-digit number having a property that With a 1 after it, it is three times as large as it would be with a one before it.

Guess the number?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

Chhote se Chintu Miyan,
Lambi si Pooch.
Jahan Jaye Chintu Miyan,
Wahan Jaye Pooch.

छोटे से चींटू मियाँ,
लंबी सी पूंछ।
जहाँ जाये चींटू मियाँ,
वहाँ जाये पूंछ।

Bolo kya?

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

Find out the number of circles in the given picture having Illusion

What number comes next in this sequence:
7 8 5 5 3 4 4 _

What kind of band never plays music?

A man desired to get into his work building, however he had forgotten his code.
However, he did recollect five pieces of information
* Fifth number + Third number = 14
* The fourth number is one more than the second number.
* The first number is one less than twice the second number.
* The second number and the third number equals 10.
* The sum of all five numbers is 30.

What is the code ?

Buy me, smell me or deliver me, I do not change.

Who am I?