In a class, the numbers of boys and girls are in the ratio of 3 : 5. What is the percentage of boys in the class?

The correct option is 37.5%.

Step-by-Step Explanation:

Step 1: Understand the given ratio
The ratio of the number of boys to the number of girls in the class is given as 3 : 5.
This means for every 3 units of boys, there are 5 units of girls.

Step 2: Find the total number of parts
To find the total number of equal parts representing the whole class, add the parts for boys and girls together:

$\text{Total parts}=3+5=8$

Step 3: Calculate the percentage of boys
The fraction of boys in the class is given by the ratio of boys' parts to the total parts:

$\text{Fraction of boys}=\frac{3}{8}$

To convert this fraction into a percentage, multiply by 100:

$\text{Percentage of boys}=\left(\frac{3}{8}\right)\times 100$

$\text{Percentage of boys}=\frac{300}{8}=37.5\%$

Thus, the percentage of boys in the class is 37.5%.