JEE Main 2021 (Online) 16th March Morning ShiftQuestion 1
A pack of cards has one card missing. Two cards are drawn randomly and are found to be spades. The probability that the missing card is not a spade, is :
Probability
Solution
By Bayes: $P=\dfrac{\frac34\cdot\binom{13}{2}}{\frac14\binom{12}{2}+\frac34\binom{13}{2}}=\dfrac{3\cdot78}{66+3\cdot78}=\dfrac{234}{300}=\dfrac{39}{50}$.