Complete the following series. It.s very logical:

1, 4, 5, 6, 7, 9, 11, __?

The captain of a ship was telling this interesting story: "We travelled the sea far and wide. At one time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly." How can that be possible?

Which is the smallest number that you can write using all the vowels exactly once?

John drives to his office at 20km/hr. After reaching the office, he realizes that today is a holiday. He went back at an average speed of 30km/hr. Discounting the time spent in the stoppage what was the average speed of his journey?

In a town, there are over 100 flats.
Flat-1 is named first flat.
Flat-2 is named second flat.
Flat-3 is named third flat.

A visitors 'Victor' decides to walk through all the flats, he finds all the flats except flat-62.
Victor later founds that the local of the town have given it another name.

What is the name of the Flat?

Why is the longest human nose just 11 inches?

As you can see that fifteen matches have been used to form an arrangement. What you have to do is remove any six of them to make them ten.

How many times in a given day, minutes and hour clock comes in a straight line ?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Find the next number in the series

12, 20, 40, 72, 116, 172 ?