Problem:
A box contains pennies, nickels and dimes. Six coins are drawn without replacement, with each coin having an equal probability of being chosen. What is the probability that the value of the coins drawn is at least cents?
Answer Choices:
A.
B.
C.
D.
E. none of these
Solution:
The number of ways of choosing coins from is . "Having at least 50 cents" will occur if one of the following cases occurs:
Six dimes are drawn.
Five dimes and any other coin are drawn.
Four dimes and two nickels are drawn.
The numbers of ways , and can occur are and , respectively. The desired probability is, therefore,