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18 Nov 2006 03:11:18 IST
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Sixteen people are arranged around a circular table. Find the no. of ways of selecting seven people so that no two of them are consecutive.
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30 Nov 2006 09:02:02 IST
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Total no. of ways of arranging 16 people around a round table is 15! Therefore selecting 7 out of 15 would be 15C7 Therfor answer is 15!/7!8!
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Nishant Bhaskar
1st year BE(Hons)
Electronics & instrumentation
BITS Pilani
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30 Nov 2006 10:15:21 IST
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16 people can be arranged on a circular table in (16-1)! i.e 15! Now in selecting 7 people such that none is consecutive would be as following First person can sit in either of the 16 chairs Second person can sit in rest of the 13 chairs Third in 11, Fourth in 9,Fifth in 7, Sixth in 5 and so on. Therefore total arrangements of the following problem will be 16*13*11*9*7*5*3=2162160
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2 Dec 2006 12:28:14 IST
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total no of ways of selecting 7 ppl frm 16 ppl is 16C7 and no of ways of having 2 consecutive ppl is 16C2 .... thrfore.. total no of ways is 16C7 - 16C2 = 11320
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6 Dec 2006 19:29:07 IST
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15,1,3,5,2,4,7,9,6,8,10,12,14,11,13,16
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7 Dec 2006 16:59:25 IST
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16 people can be arranged in 15! ways. now there are 16 spaces for 7 people. these 7 persons can be arranged in 16 spaces in16p7 ways. therefore total no. of ways of arrangement=15!*16p7
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7 Dec 2006 22:07:54 IST
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16C2
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7 Dec 2006 22:17:24 IST
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3*16=48
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Talk less work more!! {To be simplistic and 2 gain respect}
Eat less work more!!! {To "build" ur body}
Work less Do more!!! {2 make ur life big}
don't get scared !!!
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13 Dec 2006 08:03:12 IST
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16c2
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16 Dec 2006 12:19:27 IST
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ans: total no of people=16. reqd no=7 such that no two are consecutive that leaves us with 8 people and so no of selections=8C7*15!
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first person can be selected in 16c1 ways.now two persons adjacent to him cannot be selected.out of the remaining 13 persons 6 are to be selected and 7 are not to be selected.Mark + marks for persons not to be selected and they(persons not tobe selected) can be partitioned in 8 ways.out of these 8 partitions 6 are to be selected,in 8c6 ways (16c1* 8c6)/7==64 dividing by 7 implies the first person chosen may be any of the selected 7,i.e 7 times we get same selection. ans==64
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19 Dec 2006 18:33:32 IST
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15!-16/9
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19 Dec 2006 21:45:39 IST
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let the people sitting be in sequence + - + - + - + -.............+ so basically we have to select 7 signs (positive egative)out of respective number. therefore answer should be 8c7+8c7
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19 Dec 2006 21:51:30 IST
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let us consider the case of selecting a sign(+ve/-ve) out of + - + - ....+ where total signs are 17. but nou 17th sign(as it will become consicutive) similarly we select people therefore answer should be: = 2 * 8c7
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20 Dec 2006 13:08:53 IST
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since 16 people 2 must be selected but it is nothing but arranging 2 people in between 14 people round the table hence 14 gaps 14p2=91
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rvjs |
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20 Dec 2006 13:26:09 IST
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Total No. of arrangements = 16!* 8!
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21 Dec 2006 12:14:30 IST
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ans 16*13*11*9*7*6*5*3*1
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21 Dec 2006 16:30:42 IST
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15!
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21 Dec 2006 19:48:31 IST
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this ans can be solve only with the help of expert
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22 Dec 2006 09:44:27 IST
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since 16 people 2 must be selected it is nothig but arranging 2 in 14 people hence 14 gaps so selecting 14 people and arranging in table (16c2)*13! hence 14 gaps and 2 to arrange 14p2=91 answer=(14p2)*13!*(16c2)
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rvjs |
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