Total population of representative sample = 45 boys + 25 girls = 70
Now out of these 70 students, 15 girls prefer classical music.
So for 70 students = 15 girls prefer classical music
Applying unitary method,
Number of girl students preferring classical music per student = 15/70
Now we have to find number of girls preferring classical music per 350 people.
It will be given as:
[tex]\frac{15}{70}*350[/tex]
=75
Answer: If a population contains 350 people , then 75 girls prefer classical music.