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

Redeem

Functions

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 73
Joined: Tue Sep 16, 2008 4:33 pm
Thanked: 2 times

Functions

by relaxin99 » Mon Feb 23, 2009 1:21 pm
For which of the following functions is f(a + b) = f(a) + f(b)
for all positive numbers a & b?

f(x) = x
f(x) = x +1
f(x) = sr X(square root of x)
f(x) = 2/x
f(x) = -3x
Top
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 258
Joined: Thu Aug 07, 2008 5:32 am
Thanked: 16 times

Re: Functions

by x2suresh » Mon Feb 23, 2009 2:26 pm
relaxin99 wrote:For which of the following functions is f(a + b) = f(a) + f(b)
for all positive numbers a & b?

f(x) = x
f(x) = x +1
f(x) = sr X(square root of x)
f(x) = 2/x
f(x) = -3x
A.
f(a)=a
f(b)=b
f(a+b)=a+b=f(a)+f(b)
Top
Senior | Next Rank: 100 Posts
Posts: 31
Joined: Sun Oct 14, 2007 10:57 am
Thanked: 2 times

by bstalling » Mon Feb 23, 2009 2:35 pm
It could also be D.

Is something missing from A - I remember seeing this prob somewhere.

BTW try using the spoiler to include the OA.
Top
Senior | Next Rank: 100 Posts
Posts: 73
Joined: Tue Sep 16, 2008 4:33 pm
Thanked: 2 times

by relaxin99 » Mon Feb 23, 2009 3:00 pm
Its from the gmat website, from one of their practice tests. The answer is, in fact, E

f(x) = -3x

can anyone elaborate on why this is correct
Top
Master | Next Rank: 500 Posts
Posts: 301
Joined: Tue Apr 22, 2008 6:07 am
Thanked: 2 times

by beater » Mon Feb 23, 2009 3:06 pm
Try this link.

https://www.beatthegmat.com/need-help-so ... 24839.html

answer choice 1 in your post is stated incorrectly.
Top
Senior | Next Rank: 100 Posts
Posts: 73
Joined: Tue Sep 16, 2008 4:33 pm
Thanked: 2 times

by relaxin99 » Mon Feb 23, 2009 3:09 pm
Yes a) should be x^2 and not x alone, that was my mistake. thanks for that link to the explanation
Top
Post new topic Post Reply
• Page 1 of 1