CAT
Exam
Numerical Ability
a bag contains marbles of seven different colors what is the least number of marbles that a blind man must draw so that he has five marbles of same colour?
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- In order to be sure that 5marbles of same colour are drawn, let's consider that his luck was so poor that he obtained 4marbls of each colour in his first few trials.
Number of trials required to pick up 4 marbles of each colour= 7*4=28
Now , when he'll pick one more marble, he'll be sure that it would match any of the colors already picked and make that particular set attain 5 marbles.
There number of trials to be sure = 28+1=29 - 9 years agoHelpfull: Yes(2) No(0)
- 1st, He will draw 7 marbles of 7 different colors. So he has 1 marble of each color.
2nd he will draw another 7 marbles of seven different colors, now, he has 2 marbles of each color.
he repeats the same for another 3 times. So, then he will have 5 marbles of each color.
So, the blind man needs to draw (7*5)=35 marbles to have at least 5 marbles of same color - 9 years agoHelpfull: Yes(1) No(0)
- taeshika...i think ur ans z wrong becoz...here least number of marbles taken out iz asked....but u have calculated the max possible thing....drawing all d colors ....it may also happen that 1st 5 marbles taken out z of same color luckily.....
- 9 years agoHelpfull: Yes(0) No(0)
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