# Four-fifths of the pupils who took the exam passed. eighteen pupils failed the exam. how many pupils passed?

2
by dudu

• Brainly User
2015-10-01T11:16:06+08:00

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Let the total number of pupils be x.

If 5/5 is the total (whole) and 4/5 passed the exams, then 1/5 failed:
5/5 - 4/5 = 1/5

1/5 of the total pupils who failed the exams is 18:

(1/5)(x) = 18

(1/5)(x)(5/1) = 18 (5/1)     (multiply both sides of equation by 5/1, the
reciprocal of the coefficient of x)
x = (18)(5)

x =  90, the total number of pupils who took the exams.

(4/5)(90) = number of pupils who passed

360/5 = 72, the number of pupils who passed the exams
2015-10-02T20:36:29+08:00
4/5 pupils=Passed So how many is missing it is 1/5.So this is how you do it.
1/5=18
2/5=36
3/5=54
4/5=72
So 72 pupils passed.