Question

In a bag of keys, there are 13 silver keys, 6 black keys, 11 copper keys, and 2 painted keys of various colors. One key is drawn out at random. What is the probability that the key that is drawn is silver or copper?

Answer 1

The best thing to do here is to put each of these into fractions, with the total (31) as the denominator.

14/31= silver

6/31= black

8/31= copper

3/31= various colours.

As you're looking for the keys that are silver or copper, you've got to add the two denominators together, which gives you 14+8= 22.

This cannot be simplified further, therefore, the probability of choosing either a silver or copper key is 22/31

Hope this helps :)