Correct Answer: 74

Solution : Given: In a school, 60% of the students are boys and the rest are girls.
20% of the number of boys failed and 65% of the number of girls passed the examination.
Let the total number of students be 100
The number of boys = $\frac{60}{100}\times 100$ = 60
The number of girls = 100 – 60 = 40
The number of boys who passed the examination  $=\frac{80}{100}\times 60 = 48$
The number of girls who passed the examination  $=\frac{65}{100}\times 40 = 26$
The total number of students who passed = 48 + 26 = 74
The percentage of the total number of students who passed = $\frac{74}{100}\times 100$ = 74%
Hence, the correct answer is 74.