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.
How many integers between 324,700 and 458,600 have tens digi
[#permalink]
01 Jul 2020, 09:56
01 Jul 2020, 09:56
Expert Reply
00:00
Question Stats:
69% (01:28) correct
30% (02:25) wrong based on 23 sessions
Hide Show timer Statistics
How many integers between 324,700 and 458,600 have tens digit 1 and units digit 3?
A. 10,300
B. 10,030
C. 1,353
D. 1,352
E. 1,339
A. 10,300
B. 10,030
C. 1,353
D. 1,352
E. 1,339
Re: How many integers between 324,700 and 458,600 have tens digi
[#permalink]
01 Jul 2020, 09:56
01 Jul 2020, 09:56
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!
Question From Our New Project: GRE Quant Challenge Questions Daily - NEW EDITION!
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: How many integers between 324,700 and 458,600 have tens digi
[#permalink]
01 Jul 2020, 10:24
01 Jul 2020, 10:24
2
Carcass wrote:
How many integers between 324,700 and 458,600 have tens digit 1 and units digit 3?
A. 10,300
B. 10,030
C. 1,353
D. 1,352
E. 1,339
A. 10,300
B. 10,030
C. 1,353
D. 1,352
E. 1,339
A nice rule says: the number of integers from x to y inclusive equals y - x + 1
So, the number of integers from 324,700 to 458,600 = 458,600 - 324,700 + 1 = 133901
ASIDE: We can safely round this number 133900 (you'll see why shortly)
Now let's look at how frequently we have a 1 in the tens digit and 3 in the units digit.
Integers from 1 to 100: 13 (1 integer)
Integers from 101 to 200: 113 (1 integer)
Integers from 201 to 300: 213 (1 integer)
Integers from 301 to 400: 313 (1 integer)
.
.
.
As we can see, for every 100 integers, there's 1 integer with a 1 in the tens digit and 3 in the units digit.
In other words, 1/100 of all integers have a 1 in the tens digit and 3 in the units digit.
So, among the 133900 integers in question 1/100 of them meet the given condition.
(1/100)(133900) = 1339
Answer: E
Cheers,
Brent
