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

Redeem

y = 248 - 398x. Which of the following values of x gives

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: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Wed Apr 17, 2019 5:48 pm
VJesus12 wrote:$$y=248-398x$$ Which of the following values of x gives the greatest value of y in the equation above?

(A) 200
(B) 100
(C) 0.5
(D) 0
(E) -1

[spoiler]OA=E[/spoiler]

Source: GMAT Prep

We see that if x is negative, rather than subtracting 398x from 248, we are summing the values of 248 and |398x|. Thus, when x is -1, we can get the largest value of y.

Alternate solution:

We see that the given equation is a line with a negative slope (i.e., a line that is going down from left to right). Thus, the smaller the x-value, the larger the y-value. Therefore, when x is the smallest, y will be the largest. The smallest x-value given is -1 and it will yield the maximum y-value.

Answer: E

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top

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 » Thu Apr 18, 2019 7:24 am
VJesus12 wrote:$$y=248-398x$$ Which of the following values of x gives the greatest value of y in the equation above?

(A) 200
(B) 100
(C) 0.5
(D) 0
(E) -1

[spoiler]OA=E[/spoiler]

Source: GMAT Prep
We can also test the answer choices....

(A) x = 200 means y = 248 - 398(200) = some number LESS THAN 248
(B) x = 100 means y = 248 - 398(100) = some number LESS THAN 248
(C) x = 0.5 means y = 248 - 398(0.5) = some number LESS THAN 248
(D) x = 0 means y = 248 - 398(0) = some number EQUAL TO 248
(E) x = -1 means y = 248 - 398(-1) = 249 + 398 = some number GREATER THAN 248

Answer: E

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