Question

The number of groups that can be made from 5 different green balls, 4 different blue balls and 3 different red balls, if at least 1 green and 1 blue ball is to be included

• A. 3700
• B. 3720
• C. 4340
• D. 3800

Answer 1

The correct option is B

3720

At least one green ball can be selected out of 5 green balls in $2^5-1$ in 31 ways. Similarly at least one blue ball can be selected from 4 blue balls in $2^4$ - 1 = 15 ways. And at least one red or not red can be select in $2^3$= 8 ways.

Hence required number of ways =$31\times 15\times 8=3720$