A joint debating session is conducted between a certain junior class and certain senior class. What is the probability that the speaker selected at random from this group of students will be female junior?
Probability of selecting a female junior = \(\frac{Number of female juniors}{Total number of students}\)
(1) One fifth of the students are from junior class
Clearly, since a ratio is given and nothing about total number of students or about number of female juniors, the option is insufficient. Had the ratio of junior female and junior male been given then it would have made sense.
INSUFFICIENT.
(2) One fourth of the students are female students
Again only a ratio of male to female is given. No breakup for ratio of junior-senior is given.
INSUFFICIENT.
Together 1 and 2
Let total number of students = 100
Then as per statement 1 Junior students = 20 and senior students = 80
As per statement 2 female students = 25 and male students = 75
From above a lot of sets of number of Junior male, Junior female, Senior male, Senior female can be worked upon. For example - 10,10,75,15 so probability =
10/100 or 15,5,60,20 so probability =
5/100Since number of Junior female vary, probability varies.
INSUFFICIENT.
Answer E.
_________________
Ephemeral Epiphany..!
GMATPREP1 590(Q48,V23) March 6, 2019
GMATPREP2 610(Q44,V29) June 10, 2019
GMATPREPSoft1 680(Q48,V35) June 26, 2019