Bunuel wrote:
12 Days of Christmas 🎅 GMAT Competition with Lots of Questions &Fun
Three classes, Alpha, Beta, and Gamma, with no student overlap, take a test. The average (arithmetic mean) score in class Alpha is 40, in class Beta is 68, and in class Gamma is 62. The combined average score of classes Alpha and Beta is 61, while the combined average score of classes Alpha and Gamma is 42. What is the ratio of the number of students in classes Alpha, Beta, and Gamma?
A. 1:3:1
B. 1:3:10
C. 1:30:10
D. 5:15:1
E.10:30:1
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Number of students in Alpha = a
Number of students in Beta = b
Number of students in Gamma = g
(40a+68b)/(a+b) = 61
Solving we get b = 3a
(40a+62g)/(a+g) = 42
Solving we get a = 10g
b = 30g
10g : 30g :g
IMOE
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Statistics : Posted by GMATCenturion • on 19 Dec 2023, 06:00 • Replies 24 • Views 277
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