Question

There are 32 students in a class of which 12 are girls. Find:
(i) The ratio of number of boys to number of girls.
(ii) The ratio of number of boys to total number of students.

Answer 1

Hint: In this question, we are given the total number of students in a class and the number of girls in a class. We need to find two ratios. For this, we will first find the number of boys by subtracting the number of girls from the total number of students. After that, we will calculate ratio by writing the term before 'to' at first and the term after 'to' at second (after ratio sign). For simplification, we will write the ratio into division form.

Complete step by step answer:
Here, we are given the total number of students in a class as 32.
Number of girls in the class is 12.
So, let us first find the number of boys in a class.
For this, let us subtract the number of girls from the total number of students. We get,
Number of boys = 32-12 = 20.
So the number of boys is 20.
Now let us find our required ratios.
(i) The ratio of number of boys to number of girls.
Since the number of boys is written before 'to' we will write it first and number of girls will be written at second. Our ratio will look like this:
Number of boys: Number of girls.
20:12.
Let us simplify it, writing in division form we get, $\dfrac{20}{12}$.
Dividing the numerator and denominator by 4 we get $\dfrac{5}{3}$.
Hence our required ratio is 5:3.
(ii) The ratio of number of boys to total number of students.
Our ratio will look like this:
Number of boys: Total number of students.
20:32.
Let us simplify it, writing in division form we get, $\dfrac{20}{32}$.
Dividing the numerator and denominator by 4 we get, $\dfrac{5}{8}$.

Hence our required ratio is 5:8.

Note: Students should take care of the order while calculating the ratio. Make sure to simplify the ratio as much as possible. Students should note that number before 'to' is written first and the number after 'to' is written next.