A firm has 3 senior partners and 6 junior partners. How many different groups of 3 partners can be formed in which at least one member of the group is a senior partner? (Note that two groups are considered different if at least one group member is different.)
Answers:
A) 64  B) 68  C) 72  D) 76  E) 80
The number of ways to form a group of 3 is 9C3 = 84   The number of groups with no senior partner is 6C3 = 20   The number of groups with at least one senior partner is 84-20= 
<gadget id="calculator">84-20</gadget>
<output>64</output>
64   The answer is 64.
<result>A</result>
A firm has 3 senior partners and 6 junior partners. How many different groups of 3 partners can be formed in which at least one member of the group is a senior partner? (Note that two groups are considered different if at least one group member is different.)