Answer:
$ 7.7
Step-by-step explanation:
Given,
There are 18 $1 bills, ten $5 bills, eight $10 bills, three $20 bills, and one $100 bill,
Total number of bills = 18 + 10 + 8 + 3 + 1 = 40,
[tex]\because \text{Probability}=\frac{\text{Favourable outcomes}}{\text{Total outcomes}}[/tex]
Thus,
The probability of $ 1 = [tex]\frac{18}{40}[/tex]
The probability of $ 5 = [tex]\frac{10}{40}[/tex]
The probability of $ 10 = [tex]\frac{8}{40}[/tex]
The probability of $ 20 = [tex]\frac{3}{40}[/tex]
The probability of $ 100 = [tex]\frac{1}{40}[/tex]
If a bill is selected randomly,
The expected value of the bill
[tex]=\frac{18}{40}\times 1+\frac{10}{40}\times 5+\frac{8}{40}\times 10+\frac{3}{40}\times 20+\frac{1}{40}\times 100[/tex]
[tex]=\frac{18+50+80+60+100}{40}[/tex]
[tex]=\frac{308}{40}[/tex]
= $ 7.7
