Question

The students of three classes P, Q and R take a test.
The average mark per student of P. and Q put
together is 60. The average mark per student of
Q and R. put together is 64. The average mark per
student of P and R put together is 72. If the average
mark per student of all the classes put together is x,
which of the following is a possible value of x?
(A) 61.5 (B) 61.9 (C) 62.5 (D) 68.3​

Answer 1

Answer:

Let the number of students in classes A, B and C be P, Q and R respectively.

Then, total score of A = 83P, total score of B = 76Q, total score of C = 85R.

Also given that,

(83P + 76Q) / (P + Q) = 79

=>4P = 3Q.

(76Q + 85R)/(Q + R) = 81

=>4R = 5Q,

=>Q = 4P/3 and R = 5P/3

Therefore, average score of A, B, C = ( 83P + 76Q + 85R ) / (P + Q + R) = 978/12 = 81.5

Step-by-step explanation:

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