B2. The table shows the hair color of the girls in a certain class.

| Hair Color | Number of Girls |
| :--- | :---: |
| blonde | 8 |
| brown | 7 |
| red | 3 |
| black | 2 |

a) Write the percentage of girls who have red or black hair.

b) Write the percentage of girls who would need to change their hair color to black so that $20 \%$ of the girls in the class would have black hair.

c) How many redheads would need to join the class so that $32 \%$ of the class would be redheads?
B2. a) 5 students have red or black hair, which is $\frac{5}{20}$ or $25 \%$ of all students.
b) $20 \%$ of black-haired students in the class corresponds to 4 students, which means that two more students need to dye their hair black, i.e., $10 \%$.

c) If $x$ students with red hair join the class, there will be $x+3$ students with red hair. The total number of students will be $x+20$. Since $32 \%=\frac{8}{25}$, we can write the equation $\frac{3+x}{20+x}=\frac{8}{25}$. The solution to the equation is 5.

![](https://cdn.mathpix.com/cropped/2024_06_07_ec35f4a613e63419eaedg-11.jpg?height=69&width=1688&top_left_y=1322&top_left_x=227)

![](https://cdn.mathpix.com/cropped/2024_06_07_ec35f4a613e63419eaedg-11.jpg?height=62&width=1685&top_left_y=1371&top_left_x=228)

![](https://cdn.mathpix.com/cropped/2024_06_07_ec35f4a613e63419eaedg-11.jpg?height=63&width=1685&top_left_y=1422&top_left_x=228)

Calculating the percentage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 point

![](https://cdn.mathpix.com/cropped/2024_06_07_ec35f4a613e63419eaedg-11.jpg?height=68&width=1685&top_left_y=1525&top_left_x=228)

![](https://cdn.mathpix.com/cropped/2024_06_07_ec35f4a613e63419eaedg-11.jpg?height=48&width=1687&top_left_y=1575&top_left_x=230)