one year, a student council sold 856 copies of a school year book. four fifths of the students at the school bought a copy. how many students did not buy a year book
Let the number of students = S, then: 4/5S = 856 multiply both sides by 5/4 S = 1,070 total number of students 1,070 x 1/5 = 214 students who didn't buy the yearbook.
Let the number of students = S, then: 4/5S = 856 multiply both sides by 5/4 S = 1,070 total number of students 1,070 x 1/5 = 214 students who didn't buy the yearbook.
+4 
