Question

There are 4 boys 2 girls in room A and 5 boys and 3 girls in room B. A girl from one of the 2 rooms laugh loudly. What is the probability that the girl who laughed was from room B.

Answer 1

probability of room A selected=0.5
number of ways one girl of A=2
probability of room being B=0.5
ways of selecting girl from B=3c1=3
total ways of selecting one girl=5c1=5
therefore, p(girl is from B)=0.5*3/5=1.5/5=0.

Answer 2

Answer:

9/17

Step-by-step explanation:

P(R1)=1/2

P(R2)=1/2

P(G/R1)=2/6=1/3

P(G/R2)=3/8

By applying Baye's theorem,

P(R2/G)=

[(1/2×3/8)÷{(1/2×1/3)+(1/2×3/8)}]

=9/17 = Answer