To find out how many girls prefer chocolate milkshakes, we can use the information given:
- There are 40 girls in total.
- 3 out of every 5 girls prefer chocolate.
To calculate how many girls prefer chocolate, we can set up the calculation as follows:
\[ \text{Number of girls who prefer chocolate} = \text{Total girls} \times \left(\frac{3}{5}\right) \]
\[ \text{Number of girls who prefer chocolate} = 40 \times \frac{3}{5} \]
Now, we perform the multiplication:
\[ 40 \times \frac{3}{5} = 40 \times 0.6 = 24 \]
Thus, 24 girls prefer chocolate milkshakes.