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

Redeem

If f(x) = k(x - k) and k is a constant, what is the value of f(4)

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

Re: If f(x) = k(x - k) and k is a constant, what is the value of f(4)

by Brent@GMATPrepNow » Thu Feb 20, 2020 7:15 am
BTGModeratorVI wrote: ↑
Tue Feb 18, 2020 11:04 am
 If f(x) = k(x - k) and k is a constant, what is the value of f(4) - f(3), in terms of k?

(A) 1
(B) k
(C) 7k - 1
(D) k^2 + k
(E) k^2 - k

Answer: B
Source: GMAT Hacks
Given: f(x) = k(x - k)
So, for example, f(9) = k(9 - k) = 9k - k²

The question asks for the value of f(4) - f(3)
f(4) - f(3) = [k(4 - k)] - [k(3 - k)]
= [4k - k²] - [3k - k²]
= k

Answer: B

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Post new topic Post Reply
• Page 1 of 1