can you give me ratio problems please like they do on tests and give me their answers

Sure, here are some ratio problems:

1. In a bag of red and blue marbles, the ratio of red marbles to blue marbles is 3:4. If there are 12 red marbles, how many blue marbles are there?

Solution: If the ratio of red to blue marbles is 3:4, this means for every 3 red marbles, there are 4 blue marbles. If there are 12 red marbles, we can divide 12 by 3 to find out how many "groups" of red marbles there are, which is 4. Since each "group" of red marbles corresponds to 4 blue marbles, there are 4*4 = 16 blue marbles.

2. A recipe calls for 2 cups of sugar for every 5 cups of flour. How much sugar is needed if you use 15 cups of flour?

Solution: If the ratio of sugar to flour is 2:5, this means for every 2 cups of sugar, there are 5 cups of flour. If you have 15 cups of flour, you can divide 15 by 5 to find out how many "groups" of flour there are, which is 3. Since each "group" of flour corresponds to 2 cups of sugar, you need 3*2 = 6 cups of sugar.

3. The ratio of boys to girls in a class is 3:5. If there are 15 boys, how many girls are there?

Solution: If the ratio of boys to girls is 3:5, this means for every 3 boys, there are 5 girls. If there are 15 boys, we can divide 15 by 3 to find out how many "groups" of boys there are, which is 5. Since each "group" of boys corresponds to 5 girls, there are 5*5 = 25 girls.