A box contains 131 marbles. There are 39 red ones ,38 blue ones,37 green ones; the remaining 17 consist of some black ones and some white ones. If we choose marbles from the box without looking ,what is the smallest number of marbles we must pick in order to be absolutely certain that among the choosen marbles at least 21 are of the same color ?
(a) 78 (b) 115 (c) None of the others (d) 101

• Minimum number of marbles such that 21 are not of same color =>17+20+20+20 = 77
  So, if we pick up an extra marble, surely 21 will be of same color. So answer=77+1= 78
• 9 years agoHelpfull: Yes(21) No(3)
• 115 , 39+38+37+1=115.. because the average of first 3 highest is=38 but highest no. of marbles is 39. so we have to add 1 more to consider 39 marbles... now you can check the result by backtracking.i.e.(115-39-38-17 )>=21. or (115-38-37-17)=>21...
• 9 years agoHelpfull: Yes(4) No(1)
• the solution of the question in this way max(39,38,37)+ 2nd max(39,38,37)+21 of rest(37)+17=115
• 9 years agoHelpfull: Yes(3) No(2)
• c ans-39-21+38-21+37-21=51+17=68
• 9 years agoHelpfull: Yes(2) No(2)
• none of these
  since if we take 21 balls of same color then it will be the least number
• 9 years agoHelpfull: Yes(0) No(1)