Question

in a mock test 66% students passed in math and 58% in reasoning while 21% failed in both. if 225 students passed in both the subject then find total no of students appeared for test

Answer 1

out of 100 students 21 % failed
it means 79 % students passed either in maths or reasoning or in both

therefore ,
pass in maths + pass in reasoning - pass in both subjects = total pass students

66 + 58 - both pass = 79

both pass = 66+58-79

= 124 - 79

pass in both subjects = 45 %

now we have the number of students passes in both subjects = 225

45 % -------- 225

100 % -------- ?

solving we get , 100 % students = 500 students