Question

Average marks of boys in class is 52 and that of girls is 42.The average marks of boys and girls combined is 50.What is the percentage of boys in class

Answer 1

Answer:

Step-by-step explanation:

Answer 2

The percentage of boys in the class is 80%.

Step-by-step explanation:

Consider the provided information.

Let x represents the number of boys and y represents the number of girls.

The average marks of boys are 52 and average marks of girls are 42.

The average marks of boys and girls combined is 50.

This can be written as:

$\dfrac{52x+42x}{x+y}= 50$

$52x+42x= 50x+50y$

$52x-50x= 50y-42y$

$2x=8y$

$x=4y$

$\dfrac{x}{y}=\dfrac{4}{1}$

The ratio of boys and girls are 4:1

Now find the percentage.

Total number of students are x+y out of which x are boys:

$\dfrac{x}{x+y}\times100$

Substitute x =4y.

$\text{Percentage of boys}=\dfrac{4y}{4y+y}\times100$

$\text{Percentage of boys}=\dfrac{4y}{5y}\times100$

$\text{Percentage of boys}=\dfrac{4y}{5y}\times100$

$\text{Percentage of boys}=\dfrac{4}{5}\times100$

$\text{Percentage of boys}=80$

Hence, the percentage of boys in the class is 80%.

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