MathDB
Expansion of a Binomial

Source:

March 3, 2010
algebrabinomial theorem

Problem Statement

When \left ( 1 \minus{} \frac{1}{a} \right ) ^6 is expanded the sum of the last three coefficients is: (A)\ 22 \qquad (B)\ 11 \qquad (C)\ 10 \qquad (D)\ \minus{}10 \qquad (E)\ \minus{}11