Question

5) the ratio of the number of boys to the number of girls in the class is 3.4 If there are 42 student in the class, find the number of Girls?​

Answer 1

Given:

✰ The ratio of the number of boys to the number of girls in the class is 3:4

✰ Total number of students in the class are 42.

To find:

✠ The number of girls in the class.

Solution:

Let x be the number of boys in the class and y be the number of girls in the class.

Now, the ratio of the number of boys to the number of girls in the class is 3:4

According to the question,

⟹ x/y = 3/4

⟹ x = 3y/4 ...①

And, the total number of students in the class i.e, x + y are 42

⟹ x + y = 42 ...②

Substitute the value of eq ① in eq ②, we have

➤ 3y/4 + y = 42

➤ (3y + 4y)/4 = 42

➤ 3y + 4y = 42 × 4

➤ 7y = 168

➤ y = 168/7

➤ y = 24

∴ The number of girls in the class = 24 girls

If we need to find the number of boys too?

Then, we will substitute the value of number of girls in the class in eq ② i.e, total number of students in the class to get the number of boys in the class.

As,

➤ x + y = 42

➤ x + 24 = 42

➤ x = 42 - 24

➤ x = 18

∴ The number of boys in the class = 18 boys

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