Question

The average marks of three classes, a, b, and c are 30, 50, and 70, respectively. If the average marks of classes a and b together is 45, and that of classes b and c together is 65, what is the average marks of all the three classes put together​

Answer 1

The average of A,B and C is 50.

Explanation:

Given that,

The average marks of three classes, a, b, and c are 30, 50, and 70, respectively.

he average marks of classes a and b together is 45 and that of classes b and c together is 65.

Let the average marks of class A , B , C is x

The formula of average is given by :

$A=\dfrac{\text{sum of terms}}{\text{no of terms}}$

According to given condition,

$A=\dfrac{A+B+C}{3}\\\\A=\dfrac{30+50+70}{3}\\\\A=50$

So, the average of A,B and C is 50.

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