Answer
$C(5,3)=10$
Work Step by Step
All the combinations of 5 objects a,b,c,d and e taken 3 at a time is
$abc,abd, abe,acd,ace,ade,bce,bce,bde,cde$
Using the combination formula we obtain:
$C(5,3)=\frac{5!}{(5-3)!3!}=\frac{5!}{2!3!}=\frac{5\cdot4\cdot3!}{2\cdot1\cdot3!}=10$
$C(5,3)=10$
