counting digits?

by **guest612** Thu Mar 13, 2008 2:01 pm

Source: Test Code #37 pg. 8 (section 2)#15:

[Question deleted because source was not clarified - see below.]

The correct answer is E. 1,339. I arrived somewhat at that by subtracting the numbers. But I know I just got lucky! Or I don't fully understand it. I've seen similar questions in OG. Can you please help me best solve this problem (and others of the like)?

I really appreciate it!

by **gmatbeater** Thu Mar 13, 2008 5:58 pm

Hi guest612

This is the way I solved it. Not sure if it is the best approach.

From 324,700 to 325,00, there are 3 ( 324,713; 324,813 and 324,913), then from 458,000 to 458,600, there are 6 (013, 113, 213, 313, 413, and 513).
Then you can see that for every 100 you get only one integer of the type requested. So, from 325,000 to 458,000, there are 1330 hundreds. In other owrds, you have 1330 integers that meet the criteria plus the nine you obtained above, that is 1339.

I hope this helps

Regards,

[quote="guest612"]Source: Test Code #37 pg. 8 (section 2)#15:

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

The correct answer is E. 1,339. I arrived somewhat at that by subtracting the numbers. But I know I just got lucky! Or I don't fully understand it. I've seen similar questions in OG. Can you please help me best solve this problem (and others of the like)?

I really appreciate it![/quote]

by **guest612** Fri Mar 14, 2008 3:11 am

eloquently done. thanks, gmatbeater.

by **StaceyKoprince** Wed Mar 19, 2008 4:35 pm

Please cite the *author* of the test question - whose test code is that? Is that an ETS test code? If so, let us know b/c ETS pencil-and-paper tests are on the banned source list. We need to delete it so we don't get in trouble. Thanks!

by **gmatstudent** Fri Apr 11, 2008 5:44 pm

At Daifu university, 40% of all students are both members of a student organization and want to reduce their tuition costs. 20% of those students who want to reduce tuition are not members of the student organization. What percentage of all Daifu students want to reduce tuition?

* 20%
* 30%
* 40%
* 50%
* 60%

by **rfernandez** Thu Apr 17, 2008 10:34 pm

Please start a new thread for this new question. When you do so, please also include the source of the question. Thanks!

Rey

counting digits?

counting digits?

Re: counting digits?

ahhh

PR question