In a Bank officer’s selection exam 70% of the successful students qualified in the efficiency test and and 65% in the interview. If 27% wer…

Let the number of students successful in the written exam be ‘a’.

Given, 70% of the successful students, qualified in the efficiency test and 65% in the interview.

Number of students who cleared the efficiency test = 70% of a = 0.7a

Number of students who cleared the interview = 65% of a = 0.65a

Also, 27% were unsuccessful in both the exam and 248 were successful in both the exams

Number of students unsuccessful in both = 27% of a = 0.27a

Number of students successful in either one of the exams = a – 0.27a = 0.73a

⇒ Number of students qualified in efficiency test + Number of students passed in interview – Number of students successful in both = 0.73a

⇒ Number of students successful in both = 0.7a + 0.65a – 0.73a = 0.62a

Given, 248 were successful in both the exams

⇒ 0.62a = 248

⇒ a = 400