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

Redeem

OG 12 - PS Q#217

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 7
Joined: Tue Aug 09, 2011 4:54 pm

OG 12 - PS Q#217

by vkredi » Fri Oct 07, 2011 2:39 am
I did not quite understand the explanation - so, please don't repeat the solution from the OG.

In a certain game, a large container is filled with red, yellow, green and blue beads worth, 7, 5, 3, and 2 points each. A number of beads are then removed from the container. If the product of the point values of the removed beads is 147,000, how many red beads were removed?

A. 5
B. 4
C. 3
D. 2
E. 0
Top
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 496
Joined: Tue Jun 07, 2011 5:34 am
Thanked: 38 times
Followed by:1 members

by sl750 » Fri Oct 07, 2011 3:18 am
This problem uses number properties

Find the prime factors of 147000 = 2*3*5*7*7*5*2*5*2 = 2^3*3*5^3*7^2
Notice that the prime factors correspond to the points of the Red Yellow, Green and Blue beads
respectively

Red = 7 points; In 147000, we have two 7's
Yellow = 5 points; In 147000, we have three 5's
Green = 3 points; In 147000, we have one 3
Blue = 2 points; In 147000, we have 3 2's

From this we can clearly see that we have removed two 7's or 2 Red beads
Top
User avatar
GMAT Instructor
Posts: 1035
Joined: Fri Dec 17, 2010 11:13 am
Location: Los Angeles, CA
Thanked: 474 times
Followed by:365 members

by VivianKerr » Fri Oct 07, 2011 6:34 am
This has to do with factors and multiples.

7r + 5y + 3g + 2b = 147,000

We want to find the value of "r", the number of red beads removed.

Let's do a prime factorization of 147,000.

147,000 = 7 x 7 x 5 x 5 x 5 x 3 x 2 x 2 x 2

We have removed two 7's, so the answer is D.
Vivian Kerr
GMAT Rockstar, Tutor
https://www.GMATrockstar.com
https://www.yelp.com/biz/gmat-rockstar-los-angeles

Former Kaplan and Grockit instructor, freelance GMAT content creator, now offering affordable, effective, Skype-tutoring for the GMAT at $150/hr. Contact: [email protected]

Thank you for all the "thanks" and "follows"! :-)
Top
Post new topic Post Reply
• Page 1 of 1