What number comes next in the series?

5 15 5 18 5 24 14 20 _

If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

Why is the Hole below a Lock?

The following alphametic has only one solution. Can you find it?
ENLIST + SILENT + LISTEN = ANAGRAM

PS: You may start the number from 0.

A 3 digit number is such that it's unit digit is equal to the product of the other two digits which are prime. Also, the difference between it's reverse and itself is 396.

What is the sum of the three digits?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

why number 8549176320 is one of a kind?

Can you count the number of matches in the picture below ?