Answer:

12.5

Step-by-step explanation:

total score of girls = 10×15

total score of girls = 150

total score of boys = 15×10

total score of boys = 150

total score of both girls and boys = 300

total number of students in class = 10+15

total number of students in class = 25

average score of class = 300÷25

average score of class = 12.5