List of top Logical Reasoning Questions on Missing Number in Diagram asked in JEECUP

Which number among the following is a term of the given series?
Series: 3, 6, 18, 72, (?)
Which no./letter will come in place of question mark?
Which no./letter will come in place of question mark?
Which no./letter will come in place of question mark?
Which no./letter will come in place of question mark