M4maths Previous Puzzles

14 Apr 2010 Card Selection

Total number of methods of selecting 6 cards out of 10 different cards is x,
and total number of methods of selecting 6 cards out of 10 similar cards is y. Difference of x and y is

OPtion

1) 1
2) 210
3) 209
4) 60
5) 59
6) 0
7) 8
8) 69
9) 225
10) 5

Solution

Total number of methods of selecting 6 cards out of 10 different cards is
10*9*8*7*6*5/6*5*4*3*2*1 = 210
And total number of methods of selecting 6 cards out of 10 similar cards is only 1
Difference is 209

Correct Option: 3 Best Solution (9)

Dr.Dipin Singh   14 years AGO

x=10!/(6!*4!)=210
y=1
x-y=209

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Aman   14 years AGO

210-1=209

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susmit   14 years AGO

10c6-1

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sanjib biswas   14 years AGO

x=10c6 and y =1 then diference is 209

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SUDESHNA SEN   14 years AGO

Total number of methods of selecting 6 cards out of 10 different cards is x.
So, x= 10P6= (10)!/(10-6)!=210
And total number of methods of selecting 6 cards out of 10 similar cards is y.
So, y=1.
Difference of x and y is= 210-1=209.....Option 3)

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Mayur   14 years AGO

210-1=209

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Ankur Pandey   14 years AGO

x=10c6=210 and y=1 \'cos selecting any number of cards from identical things is 1 always.

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hitesh gakhar   14 years AGO

different=>10C6=210

similar=> 1

difference= 209

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karan    14 years AGO

no. of selections from identical cards =1 - nCr

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