BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

permutations

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 212
Joined: Sat Dec 01, 2007 4:19 pm
Thanked: 5 times

permutations

by vscid » Fri Feb 05, 2010 9:23 pm
A family consisting of one mother, one father, two daughters and a son is taking a road trip in a sedan. The sedan has two front seats and three back seats. If one of the parents must drive and the two daughters refuse to sit next to each other, how many possible seating arrangements are there?

(A) 28
(B) 32
(C) 48
(D) 60
(E) 120
The GMAT is indeed adaptable. Whenever I answer RC, it proficiently 'adapts' itself to mark my 'right' answer 'wrong'.
Top
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 1275
Joined: Thu Sep 21, 2006 11:13 pm
Location: Arabian Sea
Thanked: 125 times
Followed by:2 members

by ajith » Fri Feb 05, 2010 9:36 pm
vscid wrote:A family consisting of one mother, one father, two daughters and a son is taking a road trip in a sedan. The sedan has two front seats and three back seats. If one of the parents must drive and the two daughters refuse to sit next to each other, how many possible seating arrangements are there?

(A) 28
(B) 32
(C) 48
(D) 60
(E) 120
There are two possibilities

a) Parent and a girl on front; others on back seat
b) Both the girls on back separated by a parent or son


P G
_ _ _


a)If a parent is driving; there are 2 ways fill the front seat
Now if a girl is sitting in the front seat she can be selected in 2 ways
Rest of them can be arranged in 3! ways

No of ways 2*2*6 =24

P _
G1 _ G2


b) Parent can be selected in 2 ways
One to accompany in front seats can be selected in 2 ways
One who sitting in the middle can be selected in one way
Girls can be arranged in 2 ways

no of ways = 2*2*2 =8

Total ways = 8+24 =32
Always borrow money from a pessimist, he doesn't expect to be paid back.
Top
Post new topic Post Reply
• Page 1 of 1