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

Redeem

Root Addition

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Sat Sep 28, 2013 3:33 pm
The square root of 4 = 2

The cube root of 4
The cube root of 1 = 1
The cube root of 8 = 2
So, the cube root of 4 is between 1 and 2.
In other words, the cube root of 4 = 1.something

The fourth root of 4
The fourth root of 1 = 1
The fourth root of 16 = 2
So, the fourth root of 4 is between 1 and 2.
In other words, the fourth root of 4 = 1.something

TOTAL SUM = 2 + 1.something + 1.something
= more than 4
= E

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
User avatar
Legendary Member
Posts: 1556
Joined: Tue Aug 14, 2012 11:18 pm
Thanked: 448 times
Followed by:34 members
GMAT Score:650

by theCodeToGMAT » Sat Sep 28, 2013 7:53 pm
√4 = 2
(4)^1/3 = will surely be greater than (1)^1/3 .. so, 1+
(4)^1/4 = will surely be greater than (1)^1/4 .. So, 1+

M = 2 + (1+) + (1+) = 4+
Answer [spoiler]{E}[/spoiler]
R A H U L
Top

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pm
Location: Palo Alto, CA
Thanked: 2867 times
Followed by:511 members
GMAT Score:800

by [email protected] » Sat Sep 28, 2013 9:33 pm
Hi fourteenstix,

Brent's answer gives the clearest math explanation, but both explanations will get you to the correct answer. One of the ways to KNOW that you don't have to do an exact calculation is by the wording of the answer choices. In this case, since each is a "range" of values, the question itself is clue-ing you in that you don't need to do a ton of math to get the correct answer. In other questions, the word "approximate" is a clue to "round off" or estimate your math. Be on the lookout for these clues and you'll find it easier to get around the initial "shock" of what you're looking at and get to the correct answer.

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Post new topic Post Reply
• Page 1 of 1