Question

Sandi randomly selects a single bill from an envelope containing 8 ones, 5 fives, 4 tens, and 3 twenties. What is the expected value of the money she selects

Answer 1

The expected value of the money she selects is 6.65.

Explanation:

Expected value:

Sum of each outcome multiplied by its probability.

We have:

8 + 5 + 4 + 3 = 20 total bills.

8 are ones, so P(X = 1) = 8/20 = 0.4.

5 are fives, so P(X = 5) = 5/20 = 0.25.

4 are tens, so P(X = 10) = 4/20 = 0.2

3 are twenties, so P(X = 20) = 3/20 = 0.15.

What is the expected value of the money she selects?

`E(X) = 0.4*1 + 0.25*5 + 0.2*10 + 0.15*20 = 6.65`

The expected value of the money she selects is 6.65.