Combinatorics - GMAT PREP

This topic has expert replies
Source: — Problem Solving |

Master | Next Rank: 500 Posts
Posts: 135
Joined: Mon Jun 23, 2008 3:56 am
Thanked: 7 times

by sethids » Mon Sep 01, 2008 4:54 pm
There are 4C1 = 4 different ways of chosing an entree.
There are 5C2 = 10 different ways of chosing 2 side dishes.
Total combinations = 4 * 10 = 40

Junior | Next Rank: 30 Posts
Posts: 16
Joined: Mon Dec 10, 2007 8:53 pm

by sushilmore » Mon Sep 01, 2008 4:54 pm
Ans - 40

one entree is selected in 4C1 ways i.e 4 ways
2 side dishes out of 5 can be selectec in 5C2 way = 10

hence the combination = 4 X 10 = 40

Legendary Member
Posts: 594
Joined: Thu Aug 14, 2008 11:51 pm
Thanked: 12 times

by nervesofsteel » Tue Sep 02, 2008 12:44 am
4C1 * 5C2 = 40

Legendary Member
Posts: 891
Joined: Sat Aug 16, 2008 4:21 am
Thanked: 27 times
Followed by:1 members
GMAT Score:660(

by 4meonly » Wed Sep 03, 2008 8:10 am
rosh26, I think you made a mistake assuming that 1 side is needed
in that case you'll have 10 combinations