Question

Jacob stood in line to pick up a souvenir postcard at the museum. All the postcards were either blue, white, or green, with a picture of a fish, insect, or bird. There was an equal number of each type of postcard. What is the probability that Jacob was randomly handed a green postcard with a fish on it?

Answer 1

We are told there are 3 colors of postcards (blue, white or green) and 3 possible animals printed on them (fish, insect or bird).

Since each of the 3 colors can have any of the 3 animals printed on them, we can deduce there are 9 possible combinations of postcards (blue-fish, blue-insect, blue-bird, white-fish, white-insect, white-bird, green-fish, green-insect or green-bird).

Finally, we are told that there is an equal number of each type of postcard available. This means, the probabilty that Jacob was given a green-fish postcard is 1 in 9, as there is only one postcard out of all 9 possible combinations that meets the criteria.

In other words:

`P(\text{green-fish)=}(1)/(9)\approx0.1111`

Or P(green-fish)=11.11%