Question

The ratio of the number of the boy and gorl in class is 7:4 . If the number of boys is 18 more than the number of girls, what os the total number of student in class?​

Answer 1

Answer: 66 students.

Step-by-step explanation:

Given: the ratio of number of boys to the number of girls; 7:4

Let the number of boys be x

and the number of girls be y

So,

Condition 1: $\frac{x}{y} = \frac{7}{4}$

=> 4x = 7y

=> 4x -7y = 0  -----(1)

Condition 2: x = y + 18

=> x -y = 18   ----(2)

By substitution method

Sub x = y +18 in (1)

4(y+18) - 7y = 0

4y + 72 - 7y = 0

-3y = -72

y = 24

Sub y = 24 in (2)

x - 24 = 18

x = 24+18

x = 42

Therefore the number of boys is 42 and the number of girls is 24.

So, the total number of students in the class = 42 +24 = 66 students.

Hope it helps...

Mark as brainliest...

Answer 2

Given that:

• The ratio of the number of the boy and girl in class is 7 : 4.
• The number of boys is 18 more than the number of girls.

To Find:

• What is the total number of students in the class?

Let us assume:

• The number of girls be x.
• And the number of boys = x + 18

According to the question.

↠ 7 : 4 = (x + 18) : x

↠ 7/4 = (x + 18)/x

Cross multiplication.

↠ 7x = 4(x + 18)

↠ 7x = 4x + 72

↠ 7x - 4x = 72

↠ 3x = 72

↠ x = 72/3

↠ x = 24

Finding the total number of students:

Total students = Boys + Girls

↣ Total students = x + 18 + x

↣ Total students = 2x + 18

↣ Total students = 2(24) + 18

↣ Total students = 48 + 18

↣ Total students = 66

Hence,

• The total number of students in the class is 66.