Answer:
153/1015
Step-by-step explanation:
Step 1:
Representation. This is illustrated below:
Let G represent the number of girls in the class
Let B represent the number of boys in the class
Let P(G) represent the probability of girls in the class
Let P(B) represent the probability of boys in the class.
Step 2:
Data obtained from the question:
Girl (G) = 18
Boy (B) = 12
Total = 30
Step 3:
Determination of the probability of two girls followed by a boy. This is illustrated below:
The probability that the first is a girl is given by:
P(G1) = 18/30
Probability that the second is a girl is given by:
P(G2) = 17/29
Probability that the 3rd is a boy is given by:
P(B) = 12/28
Therefore, the probability of two girls followed by a boy is given by:
P(G1G2B) = 18/30 x 17/29 x 12/28
P(G1G2B) = 3672/24360
Reduce to the lowest possible term
P(G1G2B) = 153/1015
Therefore, the probability of two girls followed by a boy is 153/1015
