In a test, the average score of 50 students is 66. Out of the total students, 40% are girls and the rest are boys. The average score of the boys is 20% less than that of the girls. What is the average score of the girls?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 75.
We know that,
Average = Sum of observations/Number of observations
Let the average score of girls be 5x
The average score of boys = 4x
Number of girls = 40% of 50 = 20
According to the question;
⇒ 50 × 66 = 5x × 20 + 4x × 30
⇒ 3300 = 100x + 120x
⇒ 3300 = 220x
⇒ x = 15
Average score of girls = 5x = 5 × 15 = 75