Help with an exponent question

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anthony.j: Junior | Next Rank: 30 Posts; Posts: 26; Joined: Mon Apr 27, 2009 6:37 am; Location: South NJ, right outside of Philly; Thanked: 1 times; GMAT Score:420

by anthony.j » Sun May 03, 2009 10:54 am

Hi,

My mind is spinning right now and I can't seem to figure out how to get to this answer. Please help! Thanks!

Which of the following is equal to the value of:
2^5 + 2^5 + 3^5 + 3^5 + 3^5

answer: 2^6 +3^6

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Source: Beat The GMAT — Problem Solving | Sun May 03, 2009 10:54 am

chetanojha: Master | Next Rank: 500 Posts; Posts: 125; Joined: Sun Sep 16, 2007 1:38 pm; Thanked: 6 times

by chetanojha » Sun May 03, 2009 11:05 am

Take 2^5 and 3^5 common
2^5(1+1)+3^5(1+1+1) = 2*2^5+3*3^5 =2^6+3^6

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anthony.j: Junior | Next Rank: 30 Posts; Posts: 26; Joined: Mon Apr 27, 2009 6:37 am; Location: South NJ, right outside of Philly; Thanked: 1 times; GMAT Score:420

by anthony.j » Sun May 03, 2009 11:19 am

chetanojha wrote:Take 2^5 and 3^5 common
2^5(1+1)+3^5(1+1+1) = 2*2^5+3*3^5 =2^6+3^6

Oh, I see what you did now. After taking the common factor you are left with the two equations. Then it is simply multiplication.

So simple, yet so hard to figure it out when stuck.

Thanks!!

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cneal4: Newbie | Next Rank: 10 Posts; Posts: 8; Joined: Wed Jan 14, 2009 1:19 pm

by cneal4 » Mon May 04, 2009 7:56 am

Thanks that helped me also in understanding that a little better.

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ousek: Junior | Next Rank: 30 Posts; Posts: 20; Joined: Mon Jul 07, 2008 7:05 am; Location: Back of Beyond

Re: Help with an exponent question

by ousek » Sun Jun 28, 2009 8:09 am

anthony.j wrote: 2^5 + 2^5 + 3^5 + 3^5 + 3^5

= 2*(2^5) + 3*(3^5)
= 2^6 + 3^6

Hope this will help...

Fucking GMAT

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sudi760mba: Senior | Next Rank: 100 Posts; Posts: 85; Joined: Wed Aug 13, 2008 2:21 am; Thanked: 1 times

Re: Help with an exponent question

by sudi760mba » Thu Jul 02, 2009 12:04 am

When you have to add exponents, always factor

2^5(1 + 1) = 2^5(2) which is the same as 2^5(2^1).

With the rule
x^x * x^y = x^x + y

2^5(2^1) = 2^5+1 = 2^6

3^5(1 + 1 + 1) = 3^5(3) which is the same as 3^5(3^1)

With the rule
x^x * x^y = x^x + y

3^5(3^1) = 3^5 + 1 = 3^6

anthony.j wrote:Hi,

My mind is spinning right now and I can't seem to figure out how to get to this answer. Please help! Thanks!

Which of the following is equal to the value of:
2^5 + 2^5 + 3^5 + 3^5 + 3^5

answer: 2^6 +3^6

Like this post

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