In a class of 40 students, 45% are girls. Find the number of boys in the class .

Answer

To find the number of boys in a class of 40 students where 45% are girls, we can follow these steps:

### Step 1: Determine the total number of students.
The total number of students in the class is given as 40.

### Step 2: Calculate the percentage of boys.
Since 45% of the students are girls, we can find the percentage of boys by subtracting the percentage of girls from 100%.
\[ \text{Percentage of boys} = 100\% - 45\% = 55\% \]

### Step 3: Calculate the number of boys.
To find the number of boys, we need to calculate 55% of the total number of students (40).
\[ \text{Number of boys} = \left(\frac{55}{100}\right) \times 40 \]

### Step 4: Simplify the calculation.
\[ \text{Number of boys} = \frac{55 \times 40}{100} \]
\[ = \frac{2200}{100} = 22 \]

### Final Answer:
The number of boys in the class is **22**.

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