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

Redeem

OG #32

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
User avatar
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Thu Feb 24, 2011 1:17 pm

OG #32

by diegocuenca » Tue Jul 12, 2011 3:15 pm
sqrt((16)(20) + (8)(32)) =

For some reason I just can't get this one right. I've read the explanation but I can't figure it out. The answer is 24.

sqrt(4x4)(4x5) + (2x4)(4x4x2) =
Top
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 965
Joined: Thu Jan 28, 2010 12:52 am
Thanked: 156 times
Followed by:34 members
GMAT Score:720

by vineeshp » Tue Jul 12, 2011 6:02 pm
If you cant get it that way, just multiply the whole thing out.
It gives you sqrt(320 + 256)
which is sqrt(576) = 24.
Vineesh,
Just telling you what I know and think. I am not the expert. :)
Top
Master | Next Rank: 500 Posts
Posts: 401
Joined: Tue May 24, 2011 1:14 am
Thanked: 37 times
Followed by:5 members

by MBA.Aspirant » Wed Jul 13, 2011 1:07 am
Another way to do it:

√((16)(20) + (8)(32))

√ (16*20 + 8 * 16 *2)

√ 16 (20 + 8*2)

√ 16 * 36

4 * 6 = 24
Top
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Wed Jul 13, 2011 2:18 am
diegocuenca wrote:sqrt((16)(20) + (8)(32)) =

For some reason I just can't get this one right. I've read the explanation but I can't figure it out. The answer is 24.

sqrt(4x4)(4x5) + (2x4)(4x4x2) =
Factor out 16:
√(16*20 + 8*32)

=√(16*20 + 8*2*16)

=√(16*(20 + 8*2))

=√(16 * 36)

= 4 * 6

= 24.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
User avatar
Senior | Next Rank: 100 Posts
Posts: 32
Joined: Thu Feb 24, 2011 1:17 pm

by diegocuenca » Thu Jul 14, 2011 3:48 pm
Awesome, thanks guys.
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 20
Joined: Mon May 02, 2011 1:32 pm
Location: Bangalore
Followed by:2 members
GMAT Score:700

by kitg » Thu Jul 14, 2011 7:05 pm
easiest is factor out 16
= sqrt { (16*20) + (16*16))
= sqrt ( 16*(20+16) ) = sqrt (16*36) = 4*6 = 24
Top
Post new topic Post Reply
• Page 1 of 1