Question

Two sections A and B of a class consist of 20 and 30 students respectively. The average percentage of marks scored by the two sections respectively are 90 and 80. What is the class average percentage of marks ?

Answer 1

Answer:

84%

Step-by-step explanation:

class average

= total marks scored by two sections/ total no. of students in both section

Let the total marks scored by class A be x. Then , average percentage of class A

= x/20

90 % = x/20

Now by cross multiplication , we get the value of x to be 90 × 20 = 1800.

so total marks scored by class A = 1800

Now, let the total marks scored by class B be y.

Then, the average percentage of class B is

= y/30

80 = y/30

Now by cross multiplication, we get the value of y to be 80 × 30 = 2400

So, total marks scored by class B = 2400

Now the average percentage of the class

= marks scored by section A + marks scored by section B/ total number of students

= 1800 + 2400 / 20 + 30

= 4200 / 50

= 84

So, the average percentage of the class is 84%.

Hope this helps.