The number of costumes that can be made is 15.
A fraction is a quantity that is not a whole number. A fraction consists of a numerator and a denominator. The numerator is the number above while the denominator is the number below.
In order to determine the number of costumes that can be made, divide 11 1/4 by 3/4.
c = 11 1/4÷ 3/4
c = 45/4 x 4/3 = 15
To learn more about the division of fractions, please check: https://brainly.com/question/25779356