Question

In a bag of keys, there are 12 silver keys, 5 black keys, 10 copper keys, and 3 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

`12+5+10+3=30` <-- the number of all keys

`12+10=22` <-- the number of silver and copper keys

The probability is
`(22)/(30)=(11)/(15)`