$$y=248-398x$$ 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
y = 248 - 398x. Which of the following values of x gives
This topic has expert replies
GMAT/MBA Expert
- Scott@TargetTestPrep
- GMAT Instructor
- Posts: 7242
- Joined: Sat Apr 25, 2015 10:56 am
- Location: Los Angeles, CA
- Thanked: 43 times
- Followed by:29 members
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]
See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews
GMAT/MBA Expert
- Brent@GMATPrepNow
- 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
We can also test the answer choices....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
(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