Answer:
15 girls
Step-by-step explanation:
You first set up the ratio of boys to girls (4/5) as a fraction. Then you look. You make another fraction next to the 4/5 fraction to figure out how many girl are in the class. You know that you are trying figure out how many GIRLS are in the classroom if their are 12 boys. So on the other fraction the DENOMONATER is going to have an x on it because you don't know how many girls their are and girls (according to the fraction boys to girls (4/5) are on the bottom. So, now you cross multiply. 12x5 is 60 and 60/4 is 15. Therefore, you get 15 as your answer.