RobertMcCadden
New member
- Joined
- Sep 23, 2018
- Messages
- 2
I am studying for the PE exam and working my way through some probability questions and this one has got me stumped:
"Four military recruits whose respective shoe sizes are 7,8,9 & 10 report to the supply clerk to be issued boots. The supply clerk selects one pair of boots in each of the four required sizes and hands them at random to the recruits. What is the probability that all recruits will receive boots of an incorrect size?"
I know the total number of combinations is 4!=24, but I cannot determine how many incorrect combinations resulting in all recruits receiving the incorrect size there are without writing out all the combinations. If I look at each recruit separately the probability of the first recruit receiving the incorrect size is 3/4, but then things fall apart when I look at the second recruit because the first recruit may or may not have gotten the second recruits shoe size.
Anybody know the answer to this?
"Four military recruits whose respective shoe sizes are 7,8,9 & 10 report to the supply clerk to be issued boots. The supply clerk selects one pair of boots in each of the four required sizes and hands them at random to the recruits. What is the probability that all recruits will receive boots of an incorrect size?"
I know the total number of combinations is 4!=24, but I cannot determine how many incorrect combinations resulting in all recruits receiving the incorrect size there are without writing out all the combinations. If I look at each recruit separately the probability of the first recruit receiving the incorrect size is 3/4, but then things fall apart when I look at the second recruit because the first recruit may or may not have gotten the second recruits shoe size.
Anybody know the answer to this?