JEE Main & Advanced
Mathematics
Permutations and Combinations
Question Bank
Definition of combinations, Conditional combinations, Division into groups, Derangements
question_answer
Out of 10 white, 9 black and 7 red balls, the number of ways in which selection of one or more balls can be made, is
A)881
B)891
C)879
D)892
Correct Answer:
C
Solution :
The required number of ways are \[(10+1)(9+1)(7+1)-1=11\times 10\times 8-1=879\].