what does this picture(rebus) riddle means ?

What is a word made up of 4 letters, yet is also made up of 3. Sometimes is written with 9 letters, and then with 4. Rarely consists of 6, and never is written with 5.

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

Identify the hidden meaning behind this picture?

What is the largest amount of money that you can possess in change and still if someone asks you for a dollar, you won't be able to give?

I have Rs.50 and I spend it in the way as below.

There is a number which when you multiply by 3 and subtract 2 from the result, then the resulting number is the reverse of the actual number.

What is the smallest number that stands true on the statement?

What is common among 11, 69, and 88?

Tell me the Hindi name of a Vegetable which if we remove 1st word will become a precious Stone and by removing the last word it will become a sweet eatable.

A patient was diagnosed with some ailment. He was given five different tablets to take at night at an interval of 15 minutes.

How long will it take the patient to consume all the five tablets?