For a biased die the probabilities for different faces to turn up are given below. This die is tosse

Question

For a biased die the probabilities for different faces to turn up are given below. This die is tossed and you are told that either face 1 or face 2 has turned up. Then the probability that it is face 1 is m/n in the lowest form. find m+n

Professor PC Thomas Classes · Answer

Let $A$ be the event of face 1 turned up, $B$ be the event that face 1 or 2 has turned up.\ $P(A \cap B)=0.1$ and $P(B)=0.1+0.32=0.42$\ Required probability\ $=P(A / B)=\frac{P(A \cap B)}{P(B)}=\frac{0.1}{0.42}=\frac{5}{21}$.