Question

A box contains large no. of red, green, blue, yellow colour balls and balls of same colour are identical. The no. of ways can 10 balls be selected from the bag.

• A. $14C_{3}$
• B. $13C_{4}$
• C. $13C_{3}$
• D. $14C_{3}$

Answer 1

Answer: (C)

$13C_{3}$

Answer 2

Red, Green, Blue, Yellow

A + b + c + d = 10.

No. of ways of selection is same as no. of non-negative solutions of this equation.

No. of ways = $10 + 4 - 1C_{4 - 1} =^{13}C_{3}$.