A fair coin is tossed until a head comes up for the first time. What is the probability of this happening on an odd number tosses?

Required Probability = 1/2(First coin turns heads) + 1/2^3 (third coin turns heads) + 1/2^5(Fifth coin turns heads + .......... Required Probability = 1/2 + 1/2^3 + 1/2^5 + 1/2^7 + 1/2^9 ........ Required Probability = 1/2(1-(1/4)) = 2/3.

A tosses a fair coin 50 times. B tosses another fair coin 51 times. What is the probability that B got more heads than A?

If you toss a coin ten times and it lands heads up every time, what is the probability that it will land heads up if you toss it again?

Sachin has two coins, one of Rs. 1 denomination and the other of Rs. 2 denomination. He tosses the two coins simultaneously. What is the probability that he gets at least one head?

A coin is randomly thrown on an infinite square grid. What is the probability that the coin does not touch the grid lines? Diameter of coin : 1cm Width of square grid : 2cm