Question

If \[900\] boys and \[600\] girls appeared in an examination of which \[70\% \] of the boys and \[85\% \] of the girls passed the examination. Find the total percent of the students who did not pass?

Answer 1

Hint: In the above question we are given a certain percent of the boys and girls who passed the given exam out of the given number of boys and girls. We will first find the number of boys and girls who passed the exam. Then we add them to find the total number of students who passed the exam. Then we will proceed ahead to find the total percent of the students who did not pass.

Complete step-by-step answer:
We are given a total of \[900\] boys and \[600\] girls, who appeared in an examination. So a total of \[1500\] . Of them \[70\% \] of the boys and \[85\% \] of the girls passed the examination. So,
Number of boys who passed the examination is \[70\% \] of \[900\] given as,
 \[\dfrac{{70}}{{100}} \times 900 = 630\]
Number of girls who passed the examination is \[85\% \] of \[600\] given as,
 \[\dfrac{{85}}{{100}} \times 600 = 510\]
So a total of \[1140\] students passed the exam out of \[1500\] . So total students who do not pass are,
 \[1500 - 1140 = 360\] students.
Now to find the total percent of the students who did not pass, we find the what percent is \[360\] of \[1500\] as,
 \[\dfrac{{360}}{{1500}} \times 100 = 24\]
So a total of \[24\% \] students did not pass the exam.
So, the correct answer is “ \[24\% \] ”.

Note: When we have to find the percent we should always be very careful about the language of the question as the chances of doing the reverse calculations are very high. Also this shows that although more boys passed the exam, the percent of girls was better than boys in the exam.