Let = {1, 2,....., 20}. A subset B of is said to be "nice", if the sum of the elements of B is 203. Then the probability that a randomly chosen subset of * is "nice" is :
(1) 4/220
(2) 7/220
(3) 5/220
(4) 6/220
Correct option (3) 5/220
Explanation:
Sum of all number of set * = 210.
We have to find numbers whose sum is 203.
So basically we have to remove 7.
7 can be obtained as 7
1, 6
2, 5
3, 4
1, 2, 4
Total = 5
Samples space = 220
So 5/220.
