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.
An integer x is selected at random from the set {17, 21, 23,
[#permalink]
12 Sep 2019, 04:33
12 Sep 2019, 04:33
3
Expert Reply
2
Bookmarks
00:00
Question Stats:
73% (01:19) correct
26% (01:14) wrong based on 123 sessions
Hide Show timer Statistics
An integer x is selected at random from the set {17, 21, 23, 25, 27, 30, 33}.
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Kudos for the right answer and explanation
Quantity A |
Quantity B |
The probability that the average (arithmetic mean) of 8, 16, and x is at least 17 |
\(\frac{1}{2}\) |
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Kudos for the right answer and explanation
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: An integer x is selected at random from the set {17, 21, 23,
[#permalink]
12 Sep 2019, 10:36
12 Sep 2019, 10:36
2
Carcass wrote:
An integer x is selected at random from the set {17, 21, 23, 25, 27, 30, 33}.
Quantity A |
Quantity B |
The probability that the average (arithmetic mean) of 8, 16, and x is at least 17 |
\(\frac{1}{2}\) |
Let's first determine what x-value will yield an average of EXACTLY 17
So, we can write: \(\frac{8+16+x}{3}=17\)
Multiply both sides by 3 to get: \(8+16+x=51\)
Simplify to get: \(24+x=51\)
Solve: \(x=27\)
So, x=27 yields an average of 17
So P(average is at LEAST 17) = P(selected value is greater than or equal to 27)
In the set {17, 21, 23, 25, 27, 30, 33}, 3 of the 7 values are greater than or equal to 27
So, P(average is at LEAST 17) = P(selected value is greater than or equal to 27) = 3/7
We get:
QUANTITY A: 3/7
QUANTITY B: 1/2
1/2 > 3/7. So, the answer is B
Cheers
Brent
Re: An integer x is selected at random from the set {17, 21, 23,
[#permalink]
01 Feb 2021, 09:24
01 Feb 2021, 09:24
1
Hi,
As we need the average to be 17, So we basically need the sum to be greater than 17*3=51 and currently the sum is 51-8-16=27. Thus any number above or equal to 27 will work. Giving us a probability of 3/7 which is less than 1/2.
IMO B
As we need the average to be 17, So we basically need the sum to be greater than 17*3=51 and currently the sum is 51-8-16=27. Thus any number above or equal to 27 will work. Giving us a probability of 3/7 which is less than 1/2.
IMO B
