Question

The ratio of number of boys and girls is 4:3, If there are 18 girls in a class ,then find the total number of students in the class .
A) 40
B) 41
C) 42
D) 43

Answer 1

Hint: The ratio represents the fraction in simple form e.g ratio a:b = a/b.first find the total no of boys amongst no of students (N) with the help of ratio given here (4:3) by converting the ratio into a fraction. then add to the number of girls in order to find the total number of students.

Complete step-by-step answer:
Let the total no of students be N
Let, The number of boys be x , and the number of girls be y
N= \[x + y\]& ratio is also given i.e 4:3
Also number of girls in the class is 18 , then \[y = 18\]
\[\dfrac{x}{y} = \dfrac{4}{3}\]
\[\dfrac{4}{3} = \dfrac{x}{{18}}\]
\[x = \dfrac{{18 \times 4}}{3} = 24\]
Total no of students N =\[x + y = 24 + 18 = 42\]
There are a total of 42 students in the class.

Option C is the correct option.

Note: In the problems of ratios remember a ratio between two or more quantities is a way of measuring their value compared to each other. In mathematics, ratio indicates how many times one number is with another, a ratio may be considered as an ordered pair of numbers, a fraction with the first number in numerator and the second number written in denominator.
The ratio 40:20 is the same as the 80:40. They are just two ways of writing the same thing. Just like there are different ways of writing a fraction , there are many ways to write a ratio too. In writing the ratio the first term is called antecedent and the second term is called consequent.