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

Redeem

Romi has a collection of 10 different books that includes 7

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 298
Joined: Sun Jun 03, 2012 6:42 am
Location: New delhi
Thanked: 10 times
Followed by:7 members
GMAT Score:590

Romi has a collection of 10 different books that includes 7

by varun289 » Sat Apr 13, 2013 10:52 am
Romi has a collection of 10 different books that includes 7 same size small and 3 same size large books. The size of 1 large book is equal to the size of 3 small books. In how many ways can he select books for his trip without wasting space, if he has space available for 1 large and 4 small books?

A. 35
B. 56
C. 127
D. 196
E. 252
Top
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 511
Joined: Wed Aug 11, 2010 9:47 am
Location: Delhi, India
Thanked: 344 times
Followed by:86 members

by Anju@Gurome » Sat Apr 13, 2013 11:28 am
varun289 wrote:Romi has a collection of 10 different books that includes 7 same size small and 3 same size large books. The size of 1 large book is equal to the size of 3 small books. In how many ways can he select books for his trip without wasting space, if he has space available for 1 large and 4 small books?
He should either select {1 large book and 4 small books} or {2 large books and 1 small book} or {4 + 3 = 7 small books}

Number of ways to select 1 large book and 4 small books = (3C1)*(7C4) = 3*35 = 105
Number of ways to select 2 large books and 1 small book = (3C2)*(7C1) = 3*7 = 21
Number of ways to select 7 small books = 1

Hence, total number of possible selections = (105 + 21 + 1) = 127

The correct answer is C.
Anju Agarwal
Quant Expert, Gurome

Backup Methods : General guide on plugging, estimation etc.
Wavy Curve Method : Solving complex inequalities in a matter of seconds.

§ GMAT with Gurome § Admissions with Gurome § Career Advising with Gurome §
Top
Post new topic Post Reply
• Page 1 of 1