Elitmus
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Logical Reasoning
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Find the no. of ways you can fill a 3*3 grid(with 4 corners defined as a,b,c,d)if you have 3 white marbles,6 black marbles
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- have to put 9 marbles in nine places...and out of them 3 are of one type and 6 are of another type
so answer is 9!/(3!*6!) = 84 ways - 12 years agoHelpfull: Yes(35) No(1)
- 84 ways
There are three main possible ways of arranging the marbles -
1) BBB , BBB, WWW
Arranging these three set of marbles in three rows = 3
by keeping www in top , middle and bottom row one by one.
2) BBW , BBW , BBW
Arranging these three set of marbles in three rows = (3!/2!)*(3!/2!)*(3!/2!)=3*3*3 =27
3)BWW , BBW , BBB
Arranging these three set of marbles in three rows = 3!*(3!/2!)*(3!/2!)*(3!/3!) = 54 as all three groups are different from each other.
Total arrangements = 54 + 27 + 3 =84 - 12 years agoHelpfull: Yes(13) No(0)
- Ans: 84
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nCr = C(n,r)
Filling 9 Place with 3 white ball = C(9,3).
Remaining place is 9-3=6, thus filling rest of the place = C(9-3, 6) = 1
Total = C(9,3)*C(9-3,6) = 84*1 = 84 - 12 years agoHelpfull: Yes(12) No(0)
- Just find the ways of putting 3 white marbles at 9 possible places.
possible ways = 9C3= 9*8*7/6 = 84 ways - 12 years agoHelpfull: Yes(8) No(1)
- In addition to answer of Garima.Just find the ways of putting 3 white marbles or 6 black marbles at 9 possible places.
possible ways = 9C3 or 9C6= 9*8*7/6 = 84 ways (nCr=nCn-r) - 11 years agoHelpfull: Yes(4) No(1)
- total marbles are 9 so, 9! ways and 3 are common and 6 are common...
so,
9! / 3!*6! =9*7*8/6 =12*7=84 ways... - 10 years agoHelpfull: Yes(2) No(0)
- possible ways 9C6=84
- 7 years agoHelpfull: Yes(0) No(0)
- Firstly the question is not complete..
please ans this question in
1) 9C3
2) 6C3
3) 9C3+6C3
4) (9C3+6C3)/3!
in this - 5 years agoHelpfull: Yes(0) No(0)
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