A box I contain letters of 3 white, 1 blue and 2 yellow color another box II contain letters of 5 white, 3 blue and 4 yellow color, if all the letters are mixed in box III and 2 letters are picked without replacing, then what is the possibility that the letters are not white?
1. \(7\over 17\)
2. \(4\over 9\)
3. \(10\over 17\)
4. \(5\over 17\)
1. \(7\over 17\)
2. \(4\over 9\)
3. \(10\over 17\)
4. \(5\over 17\)
Correct Answer – Option 4 : \(5\over 17\)
Concept:
General Rule:
Calculation:
The total letters in box III = 3 + 1 + 2 + 5 + 3 + 4 = 18
Out of which:
White letters = 3 + 5 = 8
Blue letters = 1 + 3 = 4
Yellow letters = 2 + 4 = 6
Ways of selecting 2 letters out of 18 without replacement = 18C2
Ways of selecting 2 letters out of 10 not white letters without replacement = 10C2
Possibility of the letters picked are not white = \(\rm ^{10}C_2\over^{18}C_2\) = \(5\over 17\)