Question

In a certain examination 77% of students in a class passed in English and 34% failed in Mathematics. If 13% failed in both subjects and 784 passed in both the subjects. The total number of students in the class is : ___

Answer 1

% of students passed in English = 77%
$\therefore$ % failed in English = 100 - 77 = 23%
% of students, failed in both subjects = 13%
$\therefore$ % of students, failed only in English = 23 - 13 = 10%

% of students, failed only in Mathematics = 34 - 13 = 21%
$\therefore$ % of students, who have passed in both subjects = 100 - (13% + 10% + 21%)
= 56%
Number of students who have passed in both subjects = 784
$\therefore$ Total number of students $=\frac{784}{56}\times 100$ = 1400