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?

75

Ratio of number of Girls to Boys = 2 : 3

Number of girls = \(\frac{50}{5}\) × 2 = 20

Number of Boys = \(\frac{50}{5}\) × 3 = 30

Ratio of average score of boys to girls = 4 : 5

20 × 5R + 30 × 4R = 50 × 66

100R+ 120R = 3300

220R = 3300

R = 15

Average score of Girls = 5R = 5 × 15 = 75