Answer:
The odds of getting a pink marble from the 1st bag are 7/21, .333 repeating, or approximately 33%.
The odds of getting a pink marble from the 2nd bag are 3/19, .158, or approximately 16%
Explanation:
There are a total of 21 marbles in the first bag, and only 7 pink marbles. This means that when you reach into the bag, your odds are 7 out of 21 to select a pink marble. When divided, this can be changed to a percent or decimal.
There are a total of 19 marbles in the second bag, and only 3 pink marbles. When you reach into this bag, your odds are 3 out of 19 to select a pink marble. You can also divide this to become a percent or decimal.
Probability is often calculated in fraction or decimal form. If I flip a coin the odds of getting tails are 50% percent because there are only two possible outcomes, and tails is one of them. This gives you the fraction 1/2 (one-half), which is 50% when reduced.