In my class, 60% of the students only like skating and the other 40% students only like skiing. 20% of the students like skating are girls and 50% of the students like skiing are boys. What percentage of girls like skating?
Assume you have 100 students:
0.6 x 100 = 60 students like skating only.
0.4 x 100 = 40 students like skiing only.
0.2 x 60 = 12 girls who like skating.
0.5 x 40 = 20 boys who like skiing.
1 - 12 / 60 =20% of ALL students, who like skating, are girls. OR:
2 - 12 / 100 = 12% of ALL students in your class, who like skating, are girls.
Choose between (1) and (2) above, depending on what is meant.
