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.
Of the three-digit integers greater than 700, how many have
[#permalink]
02 Sep 2020, 09:47
02 Sep 2020, 09:47
Expert Reply
00:00
Question Stats:
48% (02:32) correct
51% (02:47) wrong based on 49 sessions
Hide Show timer Statistics
Of the three-digit integers greater than 700, how many have two digits that are equal to each other and the remaining digit different from the other two?
(A) 90
(B) 82
(C) 80
(D) 45
(E) 36
(A) 90
(B) 82
(C) 80
(D) 45
(E) 36
Re: Of the three-digit integers greater than 700, how many have
[#permalink]
02 Sep 2020, 09:48
02 Sep 2020, 09:48
Expert Reply
Post A Detailed Correct Solution For The Above Questions And Get A Kudos.
Question From Our New Project: GRE Quant Challenge Questions Daily - NEW EDITION!
For more theory and practice see our GRE - Math Book
Question From Our New Project: GRE Quant Challenge Questions Daily - NEW EDITION!
For more theory and practice see our GRE - Math Book
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: Of the three-digit integers greater than 700, how many have
[#permalink]
02 Sep 2020, 10:15
02 Sep 2020, 10:15
3
Carcass wrote:
Of the three-digit integers greater than 700, how many have two digits that are equal to each other and the remaining digit different from the other two?
(A) 90
(B) 82
(C) 80
(D) 45
(E) 36
(A) 90
(B) 82
(C) 80
(D) 45
(E) 36
One approach is to start LISTING numbers and look for a PATTERN.
Let's first focus on the numbers from 800 to 899 inclusive.
We have 3 cases to consider: 8XX, 8X8, and 88X
8XX
800
811
822
.
.
.
899
Since we cannot include 888 in this list, there are 9 numbers in the form 8XX
8X8
808
818
828
.
.
.
898
Since we cannot include 888 in this list, there are 9 numbers in the form 8X8
88X
880
881
882
.
.
.
889
Since we cannot include 888 in this list, there are 9 numbers in the form 88X
So, there are 27 (9+9+9) numbers from 800 to 899 inclusive that meet the given criteria.
Using the same logic, we can see that there are 27 numbers from 900 to 999 inclusive that meet the given criteria.
And there are 27 numbers from 700 to 999 inclusive that meet the given criteria. HOWEVER, the question says that we're looking at numbers greater than 700, so the number 700 does not meet the criteria. So, there are actually 26 numbers from 701 to 799 inclusive that meet the given criteria.
So, our answer is 27+27+26 = 80
Answer: C
