I have teeth but i don't bite. Who Am I ?

How can you make the following equation true by drawing only one straight line: 5+5+5=550 ?

Find the next number in the series below

21 32 54 87 131 ?

There are are five things wrong with this sentence; only geniuses will be able to to spot all of the mitstakes

What does this Rebus Picture mean?

A lion and its tamer are standing inside a cage that measures 1 unit in radius. Both of them can effortlessly run at the speed of 1 unit maximum.

1) Suppose the lion is hungry, will he be able to eat up the tamer?
2) If yes, how long can the tamer survive?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

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?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

In one of the popular batman series movie "Batman Forever", there was a riddle that goes like "Tear me off and then scratch my head and I was red then and now I am back. Who am I?