what does the below rebus means?

Andrew’s doctor gives him three pills and tells him to take one every half hour. How much time will have passed by the time Andrew’s taken all three pills?

John went to meet his friend Jacob, but when he was about to reach the main gate, John notices that Jacob had a mighty dog who was fastened to the tree. The chain is long enough that it allows the dog to reach the main gate.

How can the John reach the main gate?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

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

Who am I?

The measurement of time, That can't be found on a clock, But can be looked upon on a map.

Who is He ?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

What brings you down but never up?

What is the word or phrase below?
R | E | A | D