3. 12 a
4. 7b-10
all you have to do is add up all of the sides.
To get an equivalent fraction, multiply the fraction by a whole number. For example, you can do 2/3 times 2 to both sides which is 4/6.
Since the ratio is part-Whole, first you need to find the whole. If you add all of the marble colors together (17+13+23) you get the total marbles (53) in the box. The ratio of red marbles to the total would be 17 to 53.
