A firm has 5 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.)  Choose the correct choice: A) 130 B) 135 C) 140 D) 145 E) 150
The number of ways to form a group of 3 is 11C3 = 165   The number of groups with no senior partner is 6C3 = 20   The number of groups with at least one senior partner is 165-20= 
<gadget id="calculator">165-20</gadget>
<output>145</output>
145   The answer is 145.
<result>D</result>
A firm has 5 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.)