Bunuel
An urn contains 5 boxes. Each box contains 5 balls of different colours red, yellow, white, blue and black. Rangeela wants to pick up 5 balls of different colours, a different coloured ball from each box. If from the first box in the first draw, he has drawn a red ball and from the second box he has drawn a black ball, find the maximum number of trials that needed to be made by Rangeela to accomplish his task if a ball picked is not replaced.
A. 7
B. 11
C. 12
D. 20
E. 60
5 boxes, each containing 5 different color balls. ONE color to be picked up from each box.Now, we have already picked two colors from two boxes.
1) THIRD box: Any of the three remaining colors, Y, W or B, is to be chosen.
Worst scenario - the first two picks are R and black. So, the third has to be any of the Y, W and B.
3 picks.
2) FOURTH box: Any of the two remaining colors is to be chosen.
Worst scenario - the first three picks are color picked from first three boxes. So, the fourth has to be any of the two we are looking for.
4 picks.
3) FIFTH box: The only remaining color is to be chosen.
Worst scenario - the first four picks are color picked from first four boxes. So, the fifth has to be the color we are looking for.
5 picks.
Total ways: 3+4+5 = 12