In an examination 80% students passed. if 15 less have appeared and 10 less have passed, the ratio of passers to failures would have been 5:1. how many students passed and how many appeared in examination?
Answers
Step-by-step explanation:
p = the number of passes
f = the number of failures
p + f = the number of the people that appeared at the examination
the ratio of passes to failures was 4:1
P : f = 4 : 1
p = 4f
if 30 less had appeared and 20 less passed,the ratio of passes to failures would have been 5:1
30 less had appeared: p + f - 30
20 less passed: p - 20
number of failures: p + f - 30 - (p - 20) = p + f - 30 - p + 20 = f - 10
the ratio of passes to failures would have been 5:1
(p - 20) : (f - 10) = 5 : 1
p - 20 = 5(f - 10)
by solving the system of equations
p = 4f
p - 20 = 5(f - 10)
we find
p = 120 passes
f = 30 failures
Correct option is
C
240
Student Passed in English =80%
Students failed in English=100%−80%=20%
Students passed in Maths =70%
Students failed in Maths =100%−70%=30%
Students failed in both =10%
Total failed students = Failed in English + failed in Math − Common
Total fail students =20%+30%−10%=40%
If 40% failed then 60% will be passed.
Let total students be x.
Hence, 60% of x=144
⇒
100
60
×x=144
⇒x=
60
144×100
⇒x=240
Therefore, total students is 240.