Assume that a hat contains four bills: a $1 bill, a $5 bill, a $10 bill and a $20 bill. two bills are to be selected at a random with replacement. find the probability that
a) both bills are $1 bill if the first selected is a $1 bill
b) both bills have a value greater than a $5 bill if the second bill is a $10 bill

a)1/4

b)1/2

Step-by-step explanation:

a) The selection is with replacement, then we already have 1 $ bill and in the hat again the four bills. What is the probability  of select 1$ bill ? well it is 1/4.

The point here is,  replacement condition make the second trial totally independent of the first one

b)Following the same reasoning now we have selected a 10 $ bill, and we have two possibles positive outcome a 10 $ and a 20 $ bill and a total of 4 outcomes th th probability is 1/2

how is that middle school

step-by-step explanation: