The average score in a test for 50 students is 44. Out of the total students, 40% of the students are girls and the rest are boys. The average score of boys is 20% less than that of girls. What is the average score of girls?

Total number of students = 50
Percentage of girls = 40%
Number of girls = 50×
100
40
​
=20
Number of boys = 50−20=30

The ratio of the number of girls to boys is 20:30=2:3.

Let the average score of girls be 5x.
Since the average score of boys is 20% less than that of girls:

Average score of boys=5x×(1−
100
20
​
)=4x
Using the weighted average formula:

Overall Average=
Total number of students
(Number of girls×Avg of girls)+(Number of boys×Avg of boys)
​

44=
2+3
2×5x+3×4x
​

44=
5
10x+12x
​

44=
5
22x
​

22x=44×5
2x=10⟹x=5
Therefore, the average score of girls is:

5x=5×5=50