=there are 36 students 1/3 of them are boys also there are 3/4 of the girls that have long hair. how many girls have long hair
36 student and 1/3 are boys. 36/3 = 12 boys
36 - 12 boys means that the other 24 students must be girls.
0f those 24 girls, 3/4 of them have long hair.
24 * 3/4 = 18 girls with long hair