Question

A box contains six $1 bills, three $5 bills, two $10 bills, and seven $20 bills. What is the expectation if one bill is selected?

Answer 1

Well there are 18 bills in total...

\[\large P(\text{1 dollar bill}) = \frac{6}{18}\]
\[\large P(\text{5 dollar bill}) = \frac{3}{18}\]
\[\large P(\text{10 dollar bill}) = \frac{2}{18}\]
\[\large P(\text{20 dollar bill}) = \frac{7}{18}\]

So it looks like the bigger probability of 7/18 would say that we have a better chance of pulling out a 20 dollar bill from this box

Answer 2

6*1 = 6 value
3*5 = 15
2*10= 20
7*20= 140
----
total = 181
/18
10.0555555555556

I think 1 draw has a $10.05555 expectation

Answer 3

for a specific dollar there is a different outcome!!