Permutation and CombinationHard
Question
A box contains 2 white balls, 3 black balls & 4 red balls. In how many ways can three balls be drawn from the box if atleast one black ball is to be included in draw (the balls of the same colour are different).
Options
A.60
B.64
C.56
D.none
Solution
First we find 3 ball from 9 ball
9C3 = 84
Now number of ways if any one black ball not selected is 6C3 = 20
Here required no is 84 - 20 = 64
9C3 = 84
Now number of ways if any one black ball not selected is 6C3 = 20
Here required no is 84 - 20 = 64
Create a free account to view solution
View Solution FreeMore Permutation and Combination Questions
The number of elements in the set $S = \left\{ (r,k):k \in \mathbf{Z} \right.\ $ and $\left. \ \ ^{36}C_{r + 1} = \frac{...The sum of all numbers greater than 1000 formed by using the digits 1, 3, 5, 7 such that no digit is being repeated in a...Eleven animals of a circus have to be placed in eleven cages, one in each cage. If four of the cages are too small for s...How many five digit even numbers can be formed by using the digits 0,2,3,4,5 (Rept. not allowed)?...In how many ways can 21 identical white and 19 identical black balls be put in a row so that no two black balls are toge...