How many sides does a circle have?

The dirtier I get, the whiter I look. Who am I?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

In a jungle where there are no street lights or any other artificial source of lights, I notice a black snake crossing the road.
How did I get sight of the snake?

Which is faster, Heat or Cold ? Explain.

Bobby and Wilbur decided to take their respective car out of the garage and race. None of them cheated and they both stood at the start time and decided to cover a distance in full throttle. The first to reach the mark was to be declared the winner.

Upon reaching the finishing mark, they found out that Bobby's car was 1.2 times faster than Wilbur's. Now, Wilbur had reached the mark about 1 minute and 30 seconds later than Bobby. Bobby's car reached the mark of 60 MPH on average.

Can you calculate the distance between the starting mark and the final mark with the help of the given data?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

Can you find out which options fits best with the missing column?

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

In the given figure, you can see that four match sticks are used to form a square. Can you form five squares by using six matches?