2^(4-1)^2 / 2^(3-2)

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massi2884: Senior | Next Rank: 100 Posts; Posts: 95; Joined: Tue Sep 13, 2011 3:19 pm; Thanked: 3 times; GMAT Score:710

by massi2884 » Sat Mar 24, 2012 8:30 am

2^(4-1)^2 / 2^(3-2)

2^8
2^7
2^6
2^5
2^4

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Source: Beat The GMAT — Problem Solving | Sat Mar 24, 2012 8:30 am

seal4913: Master | Next Rank: 500 Posts; Posts: 106; Joined: Wed Mar 23, 2011 4:56 pm; Thanked: 8 times

by seal4913 » Sat Mar 24, 2012 9:55 am

So first look at (4-1) that is 3 so then you get 3 squared is 9 so it's 2^9 divided by 2^1

So when you have the same base and it's division you can subtract the exponents. So 9 - 1 = 8.

Therefore the answer is [spoiler]A 2^8[/spoiler]

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gmatmath: Junior | Next Rank: 30 Posts; Posts: 15; Joined: Mon Mar 26, 2012 12:14 am; Thanked: 3 times

by gmatmath » Fri Apr 06, 2012 8:41 am

This problem can have 2 solutions depending on how the parenthesis are placed.

case1: [2^(4-1)]^2 / 2^(3-2)
= (2^3)^2 / 2
= 2^6/2
= 2^5

case2: 2^[(4-1)^2]/2^(3-2)
= 2^[3^2]/2
= 2^9/2
=2^8

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Bill@VeritasPrep: GMAT Instructor; Posts: 1248; Joined: Thu Mar 29, 2012 2:57 pmFollowed by: 192 members; Location: Everywhere; Thanked: 503 times; GMAT Score:780

by Bill@VeritasPrep » Fri Apr 06, 2012 8:56 am

gmatmath wrote:This problem can have 2 solutions depending on how the parenthesis are placed.

case1: [2^(4-1)]^2 / 2^(3-2)
= (2^3)^2 / 2
= 2^6/2
= 2^5

case2: 2^[(4-1)^2]/2^(3-2)
= 2^[3^2]/2
= 2^9/2
=2^8

It should be the second way. See https://www.beatthegmat.com/2-4-1-2-t41974.html

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