How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?

A brand new Mobile Phone was on sale at 20% as a promotional offer. By what per cent must the Mobile price be increased to sell it at the original price again?

Place the numbers from 1 to 9 in the circles in a manner that each side of the triangle sums up to 17.

A newspaper is supposed to have 60 pages, but pages 24 and 41 are missing.
Which other pages won't be there?

If you drop me I’m sure to crack, but give me a smile and I’ll always smile back. What am I?

A car is crossing a 20 km-long bridge. The bridge can support at most 1500kg of weight over it. If somehow, the weight on the bridge becomes more than that, it will break.

Now, the weight of the car is exactly 1500kg. At the midway, a bird comes and sits on the roof of the car. This bird weighs exactly 200 grams.
Can you tell if the bridge breaks at this point or not?

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

The day after tomorrow will be three days before Tuesday. Can you find out what is today?