Situation
Four army recruits went to the supply room to get their military boots. Their shoe sizes were 7, 8, 9 & 10. The supply officer, after being informed of their sizes, prepared the four pairs of boots they need. If the boots are handed to each of the four recruits at random, what is the probability that...
 exactly 3 of them will receive the correct shoe size?

A. 1/16 
C. 1/12 
B. 1/24 
D. 0 
 all of them will receive the correct shoe size?

A. 1/16 
C. 1/12 
B. 1/24 
D. 0 
 none of them will receive the correct shoe size

A. 3/8 
C. 1/16 
B. 23/24 
D. 5/12 
Answer Key
Comments
Hi. Why does the <em>Exactly
Hi. Why does the Exactly 1 is correct, N1 = 2(4C1) = 8 is multiplied by 2? Thank you in advance for your help!
Number of ways for the three
Number of ways for the three soldiers to receive the wrong size = 2. Call the the four soldiers A, B, C and D and let A the only one who receive the correct size. B, C and D will then have two ways to receive wrong size for each of them.