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 Your Progress
every week, we’ll send you an estimated GRE score based on your performance
Practice Pays
we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:
Your score will improve and your results will be more realistic
Is there something wrong with our timer?Let us know!
The average (arithmetic mean) of y numbers is x. If 30 is ad
[#permalink]
30 Jun 2018, 09:52
1
1
Bookmarks
00:00
Question Stats:
86% (01:46) correct
13% (01:39) wrong based on 36 sessions
HideShow
timer Statistics
The average (arithmetic mean) of y numbers is x. If 30 is added to the set of numbers, then the average will be x - 5. What is the value of y in terms of x ?
Re: The average (arithmetic mean) of y numbers is x. If 30 is ad
[#permalink]
01 Jul 2018, 12:50
1st condition states that (Sum of numbers) / Total numbers (y) = x ---> Rearranging Sum of Numbers = y * x ---> (1)
2nd Condition states that (Sum of Numbers + 30) / Total Numbers (y + 1) = (x - 5) ----> Rearranging Sum of Numbers + 30 = (x - 5) * (y + 1) Substituting from (1) and solving y = x/5 - 7.....which is D above
The average (arithmetic mean) of y numbers is x. If 30 is ad
[#permalink]
08 Jul 2021, 08:22
Theory: Average = \(\frac{Sum Of All The Values}{Total Number Of Values}\)
The average (arithmetic mean) of y numbers is x Let the Sum of y numbers is denoted by \(S_y\) Using, Average = \(\frac{Sum Of All The Values}{Total Number Of Values}\), We get x = \(\frac{S_y}{y}\) => \(S_y\) = xy
30 is added to the set of numbers, then the average will be x - 5 Now, total number of numbers become y + 1 [ 30 is the extra number added to y numbers making the total number of numbers as y + 1] Sum of y+1 numbers = \(S_y\) + 30 = xy + 30 Using, Average = \(\frac{Sum Of All The Values}{Total Number Of Values}\), We get x-5 = \(\frac{xy + 30}{y+1}\) => (x-5)*(y+1) = xy + 30 => xy - 5y + x - 5 = xy + 30 => x - 5 - 30 = 5y => 5y = x - 35 => y = \(\frac{x-35}{5}\) = \(\frac{x}{5}\) - \(\frac{35}{5}\) => y = \(\frac{x}{5}\) - 7
So, answer will be D Hope it helps!
To learn more about Statistics watch the following video
gmatclubot
The average (arithmetic mean) of y numbers is x. If 30 is ad [#permalink]