There are 42 students in a class and `5/7` of the students are boys. How many girls are there in the class?

Options

A. `10`
B. `12`
C. `30`
D. `15`

Answer

To find out how many girls are in the class, we can follow these steps:

1. **Identify the total number of students**: We know that there are 42 students in total.

2. **Calculate the number of boys**: We are given that `5/7` of the students are boys. To find the number of boys, we can multiply the total number of students by the fraction representing boys:
\[ \text{Number of boys} = \frac{5}{7} \times 42 \]

3. **Perform the multiplication**:
\[ \frac{5}{7} \times 42 = \frac{5 \times 42}{7} = \frac{210}{7} = 30 \]
So, there are 30 boys in the class.

4. **Calculate the number of girls**: To find the number of girls, we subtract the number of boys from the total number of students:
\[ \text{Number of girls} = \text{Total students} - \text{Number of boys} \]
\[ \text{Number of girls} = 42 - 30 = 12 \]

5. **Conclusion**: Therefore, the number of girls in the class is 12.

### Summary of Steps:
1. Identify total students: 42
2. Calculate boys: \( \frac{5}{7} \times 42 = 30 \)
3. Calculate girls: \( 42 - 30 = 12 \)