Question

Amy has 20 necklaces in a jewelry box. The probability of reaching into the jewelry box and pulling out a silver necklace is 0.85. What is the probability that Amy will reach in the jewelry box and pull out a necklace that is not silver?

Answer 1

0.15

Explanation:

Given

`Necklaces = 20`

Represent the probability of pulling out silver with p; So:

`p = 0.85`

Required

Determine the probability of not pulling silver

This question is to test probability complements

And the complement rule of probability states that:

`p + q = 1`

Where q and p are opposites. In other words:

q = probability of not pulling out silver

Substitute 0.85 for p in
`p + q = 1`

`0.85 + q = 1`

Make q the subject

`q = 1 - 0.85`

`q = 0.15`

Hence, the required probability is 0.15