It is currently 23 Jan 2018, 07:57

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# What is the value of xy ? (1) The average of x and y is 7. (2) The ave

Author Message
TAGS:

### Hide Tags

Math Expert
Joined: 02 Sep 2009
Posts: 43377
What is the value of xy ? (1) The average of x and y is 7. (2) The ave [#permalink]

### Show Tags

10 Dec 2017, 00:11
00:00

Difficulty:

25% (medium)

Question Stats:

93% (00:27) correct 7% (00:19) wrong based on 30 sessions

### HideShow timer Statistics

What is the value of xy ?

(1) The average of x and y is 7.
(2) The average of x and -y is 1.
[Reveal] Spoiler: OA

_________________
Manager
Joined: 24 Nov 2016
Posts: 151
Re: What is the value of xy ? (1) The average of x and y is 7. (2) The ave [#permalink]

### Show Tags

10 Dec 2017, 04:49
Bunuel wrote:
What is the value of xy ?

(1) The average of x and y is 7.
(2) The average of x and -y is 1.

(1) The average of x and y is 7. $$\frac{x+y}{2}=7, x+y=14$$; x=0 y=14 xy=0 or, x=7 y=7 xy=49, not suf.

(2) The average of x and -y is 1. $$\frac{x+(-y)}{2}=1, x+(-y)=2$$; x=0 y=-2 xy=0 or, x=4 y=2 xy=8, not suf.

(3) Combine $$x+y=14, and, x+(-y)=2, 2x=16, x=8$$; substitute x in any equation, y = 6 and xy = 48, sufficient.

Intern
Joined: 16 May 2017
Posts: 17
Location: India
What is the value of xy ? (1) The average of x and y is 7. (2) The ave [#permalink]

### Show Tags

12 Dec 2017, 15:54
Bunuel wrote:
What is the value of xy ?

(1) The average of x and y is 7.
(2) The average of x and -y is 1.

As per stmt 1:

given average value of x and y is 7; (x+y)/2 =7

hence x+y = 14.possible combination for x & y are (7,7),(13,1),(1,13)..etc..in sufficient,

As per stmt 2:

given average value of x and -y is 1,hence (x-y)=2

possible combination for x and y are (3,1),(4,2)..etc in sufficient

combining both linear eqns.

we can solve linear equations from stmt1 and stmt 2 and find value of x and y

x+y=14 and x-y=1.

hence ans is C IMO
What is the value of xy ? (1) The average of x and y is 7. (2) The ave   [#permalink] 12 Dec 2017, 15:54
Display posts from previous: Sort by