Last visit was: 27 Dec 2024, 03:15 It is currently 27 Dec 2024, 03:15

Close

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

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.

Close

Request Expert Reply

Confirm Cancel
avatar
Intern
Intern
Joined: 22 Jul 2018
Posts: 39
Own Kudos [?]: 69 [17]
Given Kudos: 0
Send PM
Most Helpful Expert Reply
avatar
Supreme Moderator
Joined: 01 Nov 2017
Posts: 371
Own Kudos [?]: 471 [6]
Given Kudos: 0
Send PM
General Discussion
avatar
Retired Moderator
Joined: 20 Apr 2016
Posts: 1307
Own Kudos [?]: 2281 [4]
Given Kudos: 251
WE:Engineering (Energy and Utilities)
Send PM
avatar
Intern
Intern
Joined: 01 May 2021
Posts: 1
Own Kudos [?]: 0 [0]
Given Kudos: 1
Send PM
Re: How many numbers between 0 and 1670 [#permalink]
I tried another way, but can't see what I am missing.
The number of ways the thousand's digit can be filled is 2 - 0 and 1
For each of these ways the hundreds digit can be filled in 7 ways - 0,1,2,3,4,5,6
For each of these ways, the tens digit can be filled in 4 ways - 2,3,5,7
For each of these ways, the units digit can be filled in 4 ways - 2,3,5,7
This gives us 2x7x4x4=224 ways
But since the numbers can't cross 1670, we can subtract the 4 ways of units' digit for the 7 in tens' digit. This would give me 220 ways. Anyone who can see where I am wrong?
Intern
Intern
Joined: 15 Nov 2020
Posts: 9
Own Kudos [?]: 15 [0]
Given Kudos: 200
Send PM
Re: How many numbers between 0 and 1670 [#permalink]
RavindraShah wrote:
I tried another way, but can't see what I am missing.
The number of ways the thousand's digit can be filled is 2 - 0 and 1
For each of these ways the hundreds digit can be filled in 7 ways - 0,1,2,3,4,5,6
For each of these ways, the tens digit can be filled in 4 ways - 2,3,5,7
For each of these ways, the units digit can be filled in 4 ways - 2,3,5,7
This gives us 2x7x4x4=224 ways
But since the numbers can't cross 1670, we can subtract the 4 ways of units' digit for the 7 in tens' digit. This would give me 220 ways. Anyone who can see where I am wrong?


Using FCP we can do it like this:
_ _ (for 2 digit) = 4*4 = 16
_ _ _ (for 3 digit) = 9*4*4 = 144

But for 4 digits we will have to break it down into the range of 1000-1599 and 1600-1670 because 1577 will be included but 1677 will be not and if we try to limit the 10's digit to 3 (2,3,5) 1577 and such pairs will not be counted.
So, calculate 1000-1599 and then 1600-1670

For 1000-1599: _ _ _ _ (4 digits) = 1*6*4*4 = 96
For 1600-1670: _ _ _ _ (4 digits) = 1*1*3*4 = 12; because 1657, 1627, 1637 will be included but 1677 will not be included.

So total: 16+144+96+12 = 268
User avatar
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5092
Own Kudos [?]: 76 [0]
Given Kudos: 0
Send PM
Re: How many numbers between 0 and 1670 [#permalink]
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.
Prep Club for GRE Bot
Re: How many numbers between 0 and 1670 [#permalink]
Moderators:
GRE Instructor
88 posts
GRE Forum Moderator
37 posts
Moderator
1115 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne