Find the next number in the series below

21 32 54 87 131 ?

How many words can a pen with half refill write?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

Can you count the number of triangles in the given picture?

what's the probability of getting a king or a queen from a pack of 52 cards?

Count the number of lines in the image below ?

4 fathers, 2 grand-fathers and 4 sons went to watch the movie.What is the minimum number of tickets they need to buy ?

Why do you find that most of the buildings are deprived of the 13th floor?

If you were to put a coin into an empty bottle and then insert a cork into the neck, how could you remove the coin without taking out the cork or breaking the bottle?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?