What does this below rebus puzzle mean?

Can you make four (4) nines (9) equal 100?

What is black when you buy it, red when you use it, and gray when you throw it away?

I am a type of room you cannot enter or leave. Raised from the ground below, I could be poisonous or a delicious treat. What am I?

Who are the happiest people in IPL match?

Suppose you are a girl candidate and sitting in an interview. Suddenly the interviewer asks you, 'What if one morning you wake up and find out that you are pregnant?

How will you reply to such a question?

On her drawing table, Sayna lit 12 coloured candles. A few seconds later she blew two candles off.

How many candles Sayna have at the end?

I drive at an average speed of 30 miles per hour to the railroad station each morning and catch my train. On a particular morning, there was a lot of traffic and at the halfway point, I had averaged only 15 miles per hour. How fast must I drive for the rest of the way to catch my train?

Can you find the missing letter in the sequence?
S - T - I - L - ? - T - F - Y - C

I make two people out of one. What am I?