Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 03 Jul 2015, 14:23

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

square root of 4 x 9 + 9 x 16 / 25 0 18/5 0 12/sq.

Author Message
TAGS:
Intern
Joined: 19 Nov 2004
Posts: 44
Followers: 0

Kudos [?]: 5 [0], given: 0

square root of 4 x 9 + 9 x 16 / 25 0 18/5 0 12/sq. [#permalink]  19 Dec 2004, 17:52
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
15. square root of 4 x 9 + 9 x 16 / 25

0 18/5
0 12/sq. root of 5
0 3 * sq. root of 26 / 5
0 2 *sq. root of 3 / 5
0 6 / sq. root of 5
Manager
Joined: 19 Nov 2004
Posts: 59
Followers: 1

Kudos [?]: 3 [0], given: 0

sqrt(4x9+9x16/25)=sqrt(4x9)sqrt(1+4/25)=6/5 x sqrt(29)
Manager
Joined: 13 Dec 2004
Posts: 51
Followers: 0

Kudos [?]: 2 [0], given: 0

sqrt(4x9+9x16/25)=sqrt(4x9)sqrt(1+4/25)=6/5 x sqrt(29)

Can you explain how you got to that sqrt(4x9+9x16/25)=sqrt(4x9)sqrt(1+4/25) ???
Manager
Joined: 19 Nov 2004
Posts: 59
Followers: 1

Kudos [?]: 3 [0], given: 0

I can!
sqrt(4x9+9x16/25)=sqrt(4x9+9x4x4/25)=sqrt(4x9x(1+4/25))=sqrt(4x9)xsqrt(1+4/25)=2x3xsqrt(25/25+4/25)=6xsqrt(29/25)=6xsqrt(29)/sqrt(25)=(6/5)xsqrt(29)
Did I miss something
Manager
Joined: 13 Dec 2004
Posts: 51
Followers: 0

Kudos [?]: 2 [0], given: 0

Okay, so when you get to this:

sqrt(36(1+4/25)

I see how you can pull the 36 out, but how do you pull the 1/25 out? It looks like you multiplied the 1 by 25--which is why root 29 is in your final answer--and that you pulled (1/5) out, which is why your coefficient is 6/5. Right? But I don't understand how you can do that. Maybe this is too difficult to explain in this forum, sorry if the answer is obvious but I'm really confused.
Director
Joined: 07 Nov 2004
Posts: 690
Followers: 5

Kudos [?]: 30 [0], given: 0

I get E. 6/sqrt(5)

I think by 4 x 9 + 9 x 16 / 25 you mean (4x9 + 9x16) *1/25...
CIO
Joined: 09 Mar 2003
Posts: 463
Followers: 2

Kudos [?]: 35 [0], given: 0

gayathri wrote:
I get E. 6/sqrt(5)

I think by 4 x 9 + 9 x 16 / 25 you mean (4x9 + 9x16) *1/25...

Manager
Joined: 13 Dec 2004
Posts: 51
Followers: 0

Kudos [?]: 2 [0], given: 0

I can't get from 6 sqrt [(1 + 4/25)] to 6 over root 5.
Director
Joined: 07 Nov 2004
Posts: 690
Followers: 5

Kudos [?]: 30 [0], given: 0

hilairity wrote:
I can't get from 6 sqrt [(1 + 4/25)] to 6 over root 5.

Hilairity, I think there is a typo in the question. I think the denominator 25 applies to both the terms 4x9 and 9x16
Manager
Joined: 02 Dec 2004
Posts: 228
Followers: 1

Kudos [?]: 4 [0], given: 0

Guys,

Remember that sqrt (a+b) does not equal to sqrt a + sqrt b. They are not the same. I made that mistake initially. Write out the sqrt when you solve that question
Similar topics Replies Last post
Similar
Topics:
8 If x and y are numbers such that (x+9)(y-9)=0, what is the 4 15 Sep 2013, 11:35
13 root(x+y)=4 and root(x)-root(y)=0 22 02 Dec 2012, 13:29
15 If x<0, then square root of (-x|x|) is: 28 06 May 2010, 11:33
square root of (4 x 9 + 9 x 16) / 25 ? 18/5 12/sq. root 5 12 Jan 2007, 22:53
Display posts from previous: Sort by