SOLUTION: 4/5 of the pupils who took the exam passed. 18 pupils failed. how many pupils passed?

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Question 987726: 4/5 of the pupils who took the exam passed. 18 pupils failed. how many pupils passed?
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
4%2F5 of the pupils who took the exam passed. 

So 1-4%2F5=5%2F5-4%2F5=1%2F5 failed

18 pupils failed. 

So if there are N pupils, then since 1/5 failed,

1%2F5N = 18

Multiply both sides by 5

N = 90

how many pupils passed?

90 - 18 = 72.

Edwin