TestMagic Forums - View Single Post - A complete guide to Permutation, Combination and Probability. All you need for GMAT

shingivyas · 2007 May 1st, 05:48 PM

Hello guys!

http://www.mansw.nsw.edu.au/members...vol23no4yen.htm
the link was awesome but am stuck-
Q 1.In how many different ways can 5 boys and 4 girls sit together in a row?
a. What if Katie and Christine want to sit together

answer: Let both girls be considered as one person/seat.

Now there are only '8 people' to arrange on 8 seats. 8! = 40 320.

But for the '2-girls seat' GG, the two girls can sit in 2 different ways: G1G2 or G2G1 (Katie and Christine can swap seats). So for each of the 8! arrangements, there are 2 possibilities for GG.

a similar question says-

6 persons-3 asians, 2 european, 1 american.. they have to stand for a pic so that 3 asians are together and 2 europeans are together.. the possible no of combinations are???

2007 May 1st, 05:48 PM	#44 (permalink)
shingivyas Within my grasp! Join Date: May 2007 Posts: 250	Hello guys! http://www.mansw.nsw.edu.au/members...vol23no4yen.htm the link was awesome but am stuck- Q 1.In how many different ways can 5 boys and 4 girls sit together in a row? a. What if Katie and Christine want to sit together answer: Let both girls be considered as one person/seat. Now there are only '8 people' to arrange on 8 seats. 8! = 40 320. But for the '2-girls seat' GG, the two girls can sit in 2 different ways: G1G2 or G2G1 (Katie and Christine can swap seats). So for each of the 8! arrangements, there are 2 possibilities for GG. a similar question says- 6 persons-3 asians, 2 european, 1 american.. they have to stand for a pic so that 3 asians are together and 2 europeans are together.. the possible no of combinations are???