Question 592783
looks okay to me; why do you think it is incorrect?


there must be at least one senior ___ there are 10C1 (or 10) ways to fill this one NECESSARY spot


the remaining 5 spots on the committee may be filled by any combination of the remaining 16 students 16C5


this is a fairly straight-forward solution ___ not sure why it is not offered as one of the choices


textbooks have been known to contain errors...



O.K. , after further thought...


there are 17C6 ways to form a committee ___ (this equals 12376 ___ 10C1 * 16C5 equals 43680 , so something is amiss)


there are 7C6 ways to form a committee with NO seniors


the number of possible committees with at least one senior is ___ 17C6 - 7C6



looking at the first solution, there are duplications in the calculated value
___ eg. take seniors X, Y, and Z
___ if X was the single selection; and Y and Z were part of the final group
___ it would be the same if Y was the single; and X and Z were part of the group


sorry it took so long to figure