Question

The number of ways is which $3$ identical balls can be distributed into $7$ distinct bins is

• A. 49
• B. 84
• C. 35
• D. 42

Answer 1

Answer: (B)

Given,
$3$ identical balls can be distributed into $7$ distinct bins. i.e
$x_1+x_2+x_3+x_4+x_5+x_6+x_7=3$
$\therefore$ Total number ways :
${}^{7+3-1}{C}_{7-1}={}^9{C}_6=84$