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

Redeem

In her extensive library, Christie has 42 fantasy books, 35 science fiction books, 32 historical fiction books, and 28

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Legendary Member
Posts: 2898
Joined: Thu Sep 07, 2017 2:49 pm
Thanked: 6 times
Followed by:5 members

In her extensive library, Christie has 42 fantasy books, 35 science fiction books, 32 historical fiction books, and 28

by Vincen » Thu Oct 01, 2020 1:11 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

In her extensive library, Christie has 42 fantasy books, 35 science fiction books, 32 historical fiction books, and 28 nonfiction books. If she removes books at random, how many must she remove to guarantee that she has removed at least 35 books of the same type?

A. 77
B. 105
C. 128
D. 129
E. 144

Answer: D

Source: Veritas Prep
Top
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

Re: In her extensive library, Christie has 42 fantasy books, 35 science fiction books, 32 historical fiction books, and

by Brent@GMATPrepNow » Thu Oct 01, 2020 6:23 am
Vincen wrote: ↑
Thu Oct 01, 2020 1:11 am
 In her extensive library, Christie has 42 fantasy books, 35 science fiction books, 32 historical fiction books, and 28 nonfiction books. If she removes books at random, how many must she remove to guarantee that she has removed at least 35 books of the same type?

A. 77
B. 105
C. 128
D. 129
E. 144

Answer: D

Source: Veritas Prep
To answer this question, let's first determine the MAXIMUM number of books that can be removed WITHOUT having 35 books of the same type.

To start, we can remove all 32 historical fiction books, and 28 nonfiction books WITHOUT having 35 books of the same type.
From there, we can remove 34 fantasy books and 34 science fiction books WITHOUT having 35 books of the same type.
So far we have removed 128 books (32 + 28 + 34 + 34 = 128) and we do not have 35 books of the same type.

At this point, all that remains are 8 fantasy books, 1 science fiction book.
So, once we choose the next book, we will be GUARANTEED to have at least 35 books of the same type.
128 + 1 = 129
So, once we select 129 books, we will be GUARANTEED to have at least 35 books of the same type.

Answer: D

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1