there are five boys and ten girls in mr johnsons gym class. the simplified ratio of boys to girls is 1/2. what does this ratio mean

This ratio means for every boy there are two girls.

There are twice as many girls as there are boys. Backwards, it's there are half as many boys as there are girl.

The simplified ratio is found by reducing the ratio to the lower terms.

5/10 = 1/2

Both sides on the unsimplified ratio are division by 5. When done, it became 1/2.