Exponent Question

This topic has expert replies
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Thu Nov 13, 2008 9:53 am

Exponent Question

by ablackmon » Thu Nov 13, 2008 9:56 am
I cant seem to figure this out:

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

The test I took said the answer was 2^8 but should it be 2^5?

User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

Re: Exponent Question

by logitech » Thu Nov 13, 2008 10:02 am
ablackmon wrote:I cant seem to figure this out:

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

The test I took said the answer was 2^8 but should it be 2^5?
2^(3)^2/2^1

and here is the TRAP:

You multiplied 3x2 = 6 NO

it is 3^2 so, 3x3=9

This is why the answer is 2^(9-1) not 2^(6-1)

Hope it is clear now. It seems a like little problem but It can turn into a nightmare.
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"

Legendary Member
Posts: 940
Joined: Tue Aug 26, 2008 3:22 am
Thanked: 55 times
Followed by:1 members

Re: Exponent Question

by iamcste » Thu Nov 13, 2008 2:07 pm
ablackmon wrote:I cant seem to figure this out:

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

The test I took said the answer was 2^8 but should it be 2^5?
Tip is simplify expression first to form a ^ m ( since we know that all formulae are around this format)we often looking at such expressions, start looking out for rule and mess up

In this case ,

a. Numerator can be simplified 4-1=3
b. 3^2=9 and not 3*2=6
c. so,numerator 2^9 ( format a ^m)
d. Lets simpliy denominato

3-2=1 hence 2^1

e. (2^9 )/(2^1)

=(a^m)/(a^n)

=a^(m-n)

f. Ans=2 ^(9-1)

Ans 2^8

Note : with ample practice, you can solve such questions in mind and in few sec...

I hope my 2 cents can help

Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Thu Nov 13, 2008 10:23 pm
1) If its just a^b^c with no parantheses

Do b^c first then a ^ (b^c)



2) If its (a^b)^c then this is equal to a ^ (b*c)


Hope this also helps!