In a class, the ratio of the number of boys to that of the girls is 11 ∶ 9. 30% of the boys and 20% of the girls passed an exam. Find the percentage of students who passed the exam.

25.5%

according to question ,

ratio of ,       Boys   :   Girls

                      11    :     9

Let Number of Boys = 110 & Number of Girls = 90

Number of Passed Boys = 30% of 110 = 33

Number of Passed Girls = 20% of 90 = 18

Percentage of passed students = \(\frac{33+18}{200}\) × 100

= \(\frac{51}{200}\) × 100

= 25.5%