Question

There are 100 students in a class. Out of which 60 are boys and remaining are girls. The sum of total marks of boys is 2400 and the sum of total marks of girls is 1200. Find the ratio of average marks of boys to the average marks of girls.
1. 5 : 3
2. 5 : 4
3. 4 : 3
4. 3 : 5
5. 3 : 4

Answer 1

Correct Answer - Option 3 : 4 : 3

Given:

Total number of students = 100

Number of boys = 60

Sum of total marks of boys = 2400

Sum of total marks of girls = 1200

Concept used:

Average marks = (Sum of total Marks of students / number of students)

Calculation:

Number of Girls = Total number of students – Number of boys

⇒ Number of girls = 100 – 60

⇒ Number of girls = 40

Now, Average marks of boys = (sum of total marks of boys / Number of boys)

⇒ Average marks of boys = 2400 ÷ 60

⇒ Average marks of boys = 40

Now, Average marks of girls = (sum of total marks of girls / number of girls)

⇒ Average marks of girls = 1200 / 40

⇒ Average marks of girls = 30

Now, Ratio of average marks of boys to average marks of girls

⇒ 40 ÷ 30

⇒ 4 : 3

Alternative Solution:

For 60 Boys, total number = 2400

So each Boy got 2400 / 60 = 40 marks

For remaining 40 Girls, total number = 1200

So each Girl got 1200 / 40 = 30 marks

∴ Required ratio = 4 : 3