Gina has 20 collector stamps. 8 stamps are blue, 6 are red and 5 have both colors. If a stamp is chosen at random, what is the probability that the stamp has a blue or red color on it?
well, 19 of the 20 stamps have some blue or red, right?
To find the probability of a stamp having a blue or red color on it, we need to calculate the number of stamps that are either blue or red and divide it by the total number of stamps.
We are given that Gina has a total of 20 collector stamps, with 8 of them being blue and 6 of them being red.
However, we know that 5 of the stamps have both colors. This means that if we simply add up the number of blue and red stamps, we would be double counting those stamps that have both colors.
To avoid double counting, we need to subtract the 5 stamps that have both colors from the total number of blue and red stamps.
Number of stamps that are either blue or red = (Number of blue stamps) + (Number of red stamps) - (Number of stamps with both colors)
Number of stamps that are either blue or red = 8 + 6 - 5 = 9
Therefore, there are 9 stamps that are either blue or red.
Now, we can calculate the probability:
Probability = (Number of stamps that are either blue or red) / (Total number of stamps)
Probability = 9 / 20
Final Answer: The probability that the chosen stamp has a blue or red color on it is 9/20.
To find the probability that a stamp has a blue or red color on it, we need to find the total number of stamps that are either blue or red and divide it by the total number of stamps.
First, let's count the total number of stamps that are either blue or red. We can do this by summing the number of blue stamps and the number of red stamps, and then subtracting the number of stamps that have both colors.
Number of blue stamps = 8
Number of red stamps = 6
Number of stamps with both colors = 5
Total number of stamps that are either blue or red = Number of blue stamps + Number of red stamps - Number of stamps with both colors
= 8 + 6 - 5
= 9
Now, let's calculate the probability.
Probability = Number of stamps that are either blue or red / Total number of stamps
= 9 / 20
= 0.45
Therefore, the probability that a stamp chosen at random has a blue or red color on it is 0.45, or 45%.