What does this below rebus puzzle mean?

Decode this picture on T-Shirt and tell what it says ?

Why is 6 afraid of 7?

John asked Jack, "The time right now is 7 pm. Can you tell me what will be the time 23, 999, 995 hours later ?"

While Bella does not know the answer, do you ?

I am quite hot but become too cold if you remove the first two letters. What am I?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Why Wine Glass Stem is so long?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

Solve the below puzzle by replacing the question mark with the correct number.

3 6 12

4 8 16

5 10 ?

Find out the missing number in the picture attached: