Among 132 examinees of a certain school, the ratio of successful to unsuccessful students is 9 : 2. Had 4 more students passed, then the ratio of successful to unsuccessful students will be = ?

Answer: Option D

Total Number of student = 132
The ratio of the pass : fail = 9 : 2
Number of student pass = $$\frac{9}{11}\times 132=108$$
Number of student fail = $$\frac{2}{11}\times 132=24$$
Now 4 student more passed.
∴ Number of student pass = 108 + 4 = 112 and,
Number of student fail = 24 - 4 = 20
New ratio of pass : fail = 112 : 20 = 28 : 5