We know that you have 9 quarters
We also know that you have 21 pennies
Probability is represented as "determined factor" / total
First, we need to find the total amount of possibilities. This means that you have to add 21 and 9
21 + 9 = 30
We want to know the probability of picking a penny out of the hat, so you would represent this as:
21/30
To turn it into a percent, divide 21 by 30.
21 รท 30 = 0.7
0.7 is equivalent to 70% as a percent
This means that you will have a 70% chance of picking a penny out
Answer: 70%