fractions

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

vladmire: Master | Next Rank: 500 Posts; Posts: 132; Joined: Tue Oct 07, 2008 4:59 pm; Thanked: 4 times

by vladmire » Wed Jan 07, 2009 6:31 pm

How do you solve a power when its a fraction?

(8)^2/3 = ?

Source: Beat The GMAT — Problem Solving | Wed Jan 07, 2009 6:31 pm

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

by cramya » Wed Jan 07, 2009 6:35 pm

This is nothing but

cuberoot(8^2) = 4

Consider sqrt(4) = 4 ^ 1/2 = squarroot(4^1)

We did the same thing above

Hope this helps!

pandeyvineet24: Legendary Member; Posts: 527; Joined: Mon Jun 02, 2008 9:14 am; Location: Atlanta; Thanked: 17 times

by pandeyvineet24 » Wed Jan 07, 2009 9:55 pm

yep do a square of 8 and take its cube root.

cuberoot(8 * 8) = 4

welcome: Master | Next Rank: 500 Posts; Posts: 137; Joined: Thu Jan 08, 2009 1:27 am; Thanked: 7 times

by welcome » Thu Jan 08, 2009 6:40 am

(8)^2/3 = (2^3)^2/3 = ((2^3)^1/3)^2 = 2^2 = 4

Stuart@KaplanGMAT: GMAT Instructor; Posts: 3225; Joined: Tue Jan 08, 2008 2:40 pm; Location: Toronto; Thanked: 1710 times; Followed by:614 members; GMAT Score:800

by Stuart@KaplanGMAT » Thu Jan 08, 2009 10:24 am

welcome wrote:(8)^2/3 = (2^3)^2/3 = ((2^3)^1/3)^2 = 2^2 = 4

Good solution, using the multiplication of exponents rule:

(x^a)^b = x^(a*b)

so:

8^(2/3) = (2^3)^(2/3) = 2^(3*2/3) = 2^2 = 4

• Page 1 of 1