Blackfoot High School graduated 150
students. Approximately 15% of the senior
class did not graduate. How many seniors were
there total?
I said 173 because
150*.15= 22.5
so then 150+22.5= 72.5
so approximately it would be 173 right?

Question

Blackfoot High School graduated 150 
students. Approximately 15% of the senior 
class did not graduate. How many seniors were 
there total? 
I said 173 because
150*.15= 22.5
so then 150+22.5= 72.5
so approximately it would be 173 right?

anonymous · Answer

15% no graduate, means 85% graduated
85% = 150
1%  = 150/85
100% = (150/85) x 100 = 176.47, but you cannot have 0.47 persons, so roudned down to 176

anonymous · Answer

100% = 100 units = total number of students
15% = 15 units = number of students that did not graduate
100%-15% = 85% = 85 units = number of students that graduated

If 150 students graduated, this represents 85 units.
Find 100 units to find total number of students

85 units = 150
1 unit = 150 / 85 = 1.764705882
100 units = 176.4705

jim_thompson5910 · Answer

let x = total number of seniors

15% did not graduate, so 100 - 15 = 85% did graduate

85% of x = 0.85x = number who graduated

so this means

0.85x = 150

x = 150/0.85

x = 176.470588235294

round this to the nearest whole number to get 176

so there are roughly 176 seniors