Question

The total number of students of class a and b is 110 and number of students in class a is 10 more than b if average score of b in a test is 20% more than a and total average is 72 find average of class a

Answer 1

Average score of class A students is 66

Step-by-step explanation:

Let class A has x students and class B has y students

According to the question,

x + y = 110 ..... (1)

x = y + 10 ..... (2)

Using (1) and (2), we get

y + 10 + y = 110

or, 2y = 100

or, y = 50

Then x = 110 - 50 = 60

Thus class A has 60 students and class B has 50 students.

Given that, average score of all the students is 72

Then total score of all the students is

= 110 × 72 = 7920

Let class A students have gotten an average score of p

Then total score of class A students is 60p

By the given condition, average score of class B students is 20% more than class A students. Then class B students have an average score of

= p (1 + 20/100)

= p (1 + 1/5)

= 6p/5

Then total score of class B students is

= 50 * 6p/5

= 60p

Then,

60p + 60p = 7920

or, 120p = 7920

or, p = 66

∴ average score of class A students is 66 and that of class B students is (6 * 66/5 =) 79.2