GMAT Prep Probability

moneyman · Posted: Sat May 10, 2008 7:49 am Post subject: GMAT Prep Probability

In a certain group of 10 members , 4 members teach only French and the rest teach only Spanish or German. If the group is to choose a 3-member committee , which must have atleast 1 member who teaches French, how many different committees can be chosen ?

40
50
64
80
100

Ans E

CITI29 · Posted: Sun May 11, 2008 11:54 pm Post subject:

1-french and 2 other language : 4!/1!3! * 6!/2!4! = 4*15= 60
2-french and 1 other langauage : 4!/2!2! * 6!/1!5! =6*6= 36
All 3 french : 4!/3!1! = 4

Add all three outcomes : 60+36+4 = 100

correct ans [E]