Permutations , combinations and binomial expansion Statistics - Permutations , combinations and binomial expansion

• ✓
  $3$
• B
  $\frac{1}{6}$
• C
  $2$
• D
  $\frac{1}{3}$

Answer: A.

• A
  $n !$
• B
  $(n-1) !$
• C
  $\frac{1}{n !}$
• ✓
  $\frac{1}{(n-1) !}$

Answer: D.

• A
  $-5$
• B
  $719$
• ✓
  $0$
• D
  $720$

Answer: C.

• A
  $6$
• ✓
  $3$
• C
  $4$
• D
  $9$

Answer: B.

• A
  $120$
• B
  $6 \times 5$
• ✓
  $6 \times 5$ !
• D
  $6 \times 5 \times 4 \times 3$

Answer: C.