Question

In a class the ratio of the number of boys and that of the girls is 11:9. If 30% of the boys and 20% of the girls are passed. Find the percentage of passed students of the class.

Answer 1

Answer:

Step-by-step explanation:

Answer 2

Given: Ratio of boys and girls in class = 11 : 9

          Percentage of boys who passed = 30%

          Percentage of female students who passed = 20%

To Find: Percentage of passed students of the class.

Solution:

Let x be the common factor.

∴ Number of boys = 11x

  Number of female students = 9x

  Total number of students = 11x + 9x

                                               = 20x  

∴Number of boys who passed = 30% of 11x

                                                = $\frac{30}{100} \times 11x$

                                                = $\frac{33x}{10}$

Number of females students who passed = 20% of 9x

                                               = $\frac{20}{100} \times 9x$

                                               = $\frac{18x}{10}$

∴ Total number of students who passed = $\frac{33x}{10} +\frac{18x}{10}$

                                                                =  $\frac{51x}{10}$

∴ Percentage of passed students = $\frac{Students who passed}{Total number of students} \times 100$

                                                     =  $\frac{\frac{51x}{10} }{20x} \times 100 %$ %

                                                     = $\frac{51x}{10} \times\frac{1}{20x} \times 100$%

                                                     = $\frac{51}{2}$%

                                                     = 25.5%

Answer: 25.5% of students passed in the class.