Chapter 10 - Section 10.2 - Permutations and Combinations - 10.2 Assess Your Understanding - Page 695: 29

$C(4,3)=4$

All the combinations of 4 objects 1,2 3 and 4 taken 3 at a time is $123,124,134,234$ so using the combination formula we obtain: $C(4,3)=\frac{4!}{(4-3)!3!}=\frac{4!}{1!3!}=\frac{4\cdot3!}{1!3!}=4$ $C(4,3)=4$