Question

Six identical coins are arranged in a row. The number of ways in which the number of tails is equal to the number of heads is

• A. $20$
• B. $9$
• C. $120$
• D. $40$

Answer 1

Answer: (A)

$20$

Answer 2

Required number of ways $=\frac{6!}{3!\,3!}=\frac{720}{6\times6}=20$