Answer: there are 24 girls.
Step-by-step explanation:
Let x represent the number of boys in fifth grade at lenape elemantary school.
In fifth grade at lenape elemantary school,there are 4/7 as many girls as there are boys. This means that the number of girls in the school would be
4/7 × x = 4x/7
There are 66 students in fifth grade. This means that
x + 4x/7 = 66
Cross multiplying by 7, it becomes
7x + 4x = 462
11x = 462
x = 462/11
x = 42
The number of girls would be
66 - 42 = 24