GRE Prep 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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
If the average of x and y equals 40, the average of y and z
[#permalink]
22 Jul 2019, 09:10
22 Jul 2019, 09:10
Expert Reply
2
Bookmarks
00:00
Question Stats:
87% (01:29) correct
12% (01:47) wrong based on 87 sessions
Hide Show timer Statistics
If the average of x and y equals 40, the average of y and z equals 60, and the average of x, y, and z equals 30, then the average of x and z equals what?
Show: :: OA
-10
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
If the average of x and y equals 40, the average of y and z
[#permalink]
23 Jul 2019, 06:52
23 Jul 2019, 06:52
2
1
Bookmarks
Carcass wrote:
If the average of x and y equals 40, the average of y and z equals 60, and the average of x, y, and z equals 30, then the average of x and z equals what?
Show: :: OA
-10
The average of x and y equals 40
We can write: (x+y)/2 = 40
Multiply both sides by 2 to get: x + y = 80
The average of y and z equals 60
We can write: (y+z)/2 = 60
Multiply both sides by 2 to get: y + z = 120
The average of x, y, and z equals 30
We can write: (x+y+z)/3 = 30
Multiply both sides by 3 to get: x + y + z = 90
IMPORTANT: We need to find the sum of x and z
Take:
x + y + z = 90
y + z = 120
Subtract the bottom equation from the top equation to get: x = -30
Take:
x + y + z = 90
x + y = 80
Subtract the bottom equation from the top equation to get: z = 10
Average of x and z = (x + z)/2 = [(-30) + 10]/2 = (-20)/2 = -10
Answer: -10
RELATED VIDEO
Re: If the average of x and y equals 40, the average of y and z
[#permalink]
27 Jul 2024, 05:48
27 Jul 2024, 05:48
Hello from the GRE Prep Club BumpBot!
Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
