I have two coins.
* One of the coin is a faulty coin having tail on both side of it.
* The other coin is a perfect coin (heads on side and tail on other).
I blind fold myself and pick a coin and put the coin on table. The face of coin towards the sky is tail.
What is the probability that other side is also tail ?
2/3
2 possible scenario are :
case number side shown other side
1 A1 (H) A2 (H)
2 A2 (H) A1 (H)
3 B1 (H) B2 (T)
4 B2 (T) B1 (H)
case 4 is not possible so ans is 2/3
