In how many different ways can a group of 8 people be divided into 4 teams of 2 people each? Choose the most appropriate option:
A) 90 B) 105 C) 168 D) 420 E) 2520
You need to choose 4 groups of 2 from 8 people: That's 8/!2!2!2!2!, then divided by 4!, since any ordering of these 4 groups is the same.   Total = 8/2!2!2!2!4!=8!/8∗2∗4!=7!/2∗4!=7∗6∗5∗4∗3∗2/4∗3∗2∗2=7∗6∗5/2=35∗3=105.   Answer: 105
<result>B</result>
In how many different ways can a group of 8 people be divided into 4 teams of 2 people each?