The ratio of boys to students is 3 to 7. If there are 20 girls in the school, then how many boys are in the school?

Find the domain and range of the following function f(x) = 51x - 21+ 4

Simplify the given expression leaving the answer in improper fraction form. 2/3+5/6

Lucy is a dress maker. she sews \dfrac47 7 4 ? of a dress in \dfrac34 4 3 ? hour. lucy sews at a constant rate. at this rate, how many dresses does lucy sew in one hour? include fractions of dresses if applicable.