Bunuel wrote:
If a student is selected at random from Learngood Elementary, what is the probability that the student will be a boy?
(1) There are 480 students at Learngood.
(2) At Learngood, the ratio of boys to girls is 7:5
Target question: What is the probability that the (selected) student will be a boy? Statement 1: There are 480 students at Learngood. Since we have no information about the number of boys at the school, statement 1 is NOT SUFFICIENT
Statement 2: At Learngood, the ratio of boys to girls is 7:5This tells us that, for every 12 children at the school, 7 are boys, and 5 are girls.
In other words, 7/12 of the students at the school are boys, which means
P(selected student is a boy) = 7/12Since we can answer the
target question with certainty, statement 2 is SUFFICIENT
Answer: B
Cheers,
Brent
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Brent Hanneson – Creator of gmatprepnow.com
I’ve spent the last 20 years helping students overcome their difficulties with GMAT math, and the biggest thing I’ve learned is…
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