Question

in an examination 80% students passed in maths,72% passed in science and 13% failed in both the subjects. if 312 students passed in both the subjects find the total number of students who oppossed in the examination

Answer 1

Solution :-

Given : In an examination 80% students passed in maths,72% passed in science and 13% failed in both the subjects.

Number of students failed only in maths = (100 - 80)% - 13% = 20% - 13% = 7%

Num

Number of students failed in only science = (100 - 72)% - 13% = 28% - 13% = 15%

Total percentage of failed students = (7 + 15 + 13)% = 35%

Total percentage of passed students = (100 - 35)% = 65%

Total students passed in both the subjects = 312

Let the total number of students appeared in exam be x.

According to the question,

=> 65% of x = 312

=> 0.65x = 312

=> x = 312/0.65 = 480

Hence,

The total number of students who oppossed in the examination = 480

Answer 2

» Let total number of students be M.

• Number of students pass in math = 80% of M

=> 80/100 × M

=> 0.8 M

• Number of students pass in science = 72% of M

=> 72/100 × M

=> 0.72 M

• Number of students failed in both (maths and science) = 13% of M

=> 13/100 × M

=> 0.13 M

• Number of students pass in both (maths and science) = 312

=> 0.8M + 0.72M + 0.13M = 1.65 M

Now..

100 - 1.65 = 0.65

» 312 students passed in both the subjects.

=> 0.65 M = 312

=> M = 312/0.65

=> M = 480

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480 students opposed in the examination.

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