Statistics-And-Probability Question 645
Question: Students of two schools appeared for a common test carrying 100 marks. The arithmetic means of their marks of school I and II are 82 and 86 respectively. If the number of students of school II is 1.5 times the number of students of school I, what is the arithmetic mean of the marks of all the students of both are schools?
Options:
A) 84.0
B) 84.2
C) 84.4
D) This cannot be calculated with the given data
Show Answer
Answer:
Correct Answer: C
Solution:
[c] Let the number of students of school I = x
$ \therefore $ Number of students of school II=1.5 x As given: Mean of marks for school $ I=82 $ and mean of marks for school II = 86
$ \therefore $ Combined mean = $ \frac{x\times 82+1.5x\times 86}{x+1.5x} $ $ =\frac{x(82+129)}{2.5x}=\frac{211}{2.5}=84.4 $
BETA
