P&C Challenge 7

JEE Advanced Tutorials › Algebra questions › P&C Challenge 7

Find the number of ways of selecting n objects out of 3n objects,of which n are alike and rest are different

#Mathematics #Algebra

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7 Answers

62

Lokesh Verma ·2009-10-21 05:26:03

This I think is from A das gupta.. someone asked this to me recently

Hint: chose r of the different objects.. the rest (n-r) can be chosen in only 1 way..

so you will have a summation....

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1

Rocky Crazy ·2009-10-21 05:29:37

Ok i will try dis way..

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Rocky Crazy ·2009-10-21 05:30:16

I got it frm Arihant..They keep copying frm one place to other..

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msp ·2009-10-21 05:32:12

dude most of the buks specially for iit jee do this job.

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106

Asish Mahapatra ·2009-10-26 03:35:15

is the answer this?

²ⁿC_n + ²ⁿC_n-1 + ²ⁿC_n-2 + ... + ²ⁿC₁ + ²ⁿC₀

= 2^n-1 ?? (just for my verification)

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RAY ·2009-10-26 03:42:36

yah ashish i think u r right !!

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Rocky Crazy ·2009-10-26 06:35:36

Yeah Ashish correct..

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Your Answer

Basic Integral Calculus Operators Symbols Matrix Cases

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