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.
number system
[#permalink]
06 May 2016, 23:28
06 May 2016, 23:28
00:00
Question Stats:
91% (01:11) correct
8% (00:15) wrong based on 12 sessions
Hide Show timer Statistics
number of numbers between 200 and 600 that are divisible by 13?
official answer provided is 31 numbers.
so,please help in providing the answer with proper expkination.
official answer provided is 31 numbers.
so,please help in providing the answer with proper expkination.
Re: number system
[#permalink]
07 May 2016, 00:57
07 May 2016, 00:57
2
Expert Reply
Solution
Here we have to find number of multiples of 13 between 200 and 600.
Now 200/13 = 15.38 Hence we can say that any integer larger than 15.38 when multiplied by 13 has a value greater than 200.
So 16*13 is the first multiple of 13 in range 200 - 600.
N0w again 600/13 = 46.15. Similarly any integer less than 46.15 when multiplied by 13 has a value less than 600.
So 46*13 is the last multiple of 13 in range 200 - 600.
Hence Number of multiple of 13 in range 200 - 600 = 46 - 16 + 1 (+1 to include the first or the last term) = 31
Here we have to find number of multiples of 13 between 200 and 600.
Now 200/13 = 15.38 Hence we can say that any integer larger than 15.38 when multiplied by 13 has a value greater than 200.
So 16*13 is the first multiple of 13 in range 200 - 600.
N0w again 600/13 = 46.15. Similarly any integer less than 46.15 when multiplied by 13 has a value less than 600.
So 46*13 is the last multiple of 13 in range 200 - 600.
Hence Number of multiple of 13 in range 200 - 600 = 46 - 16 + 1 (+1 to include the first or the last term) = 31
Director
Joined: 16 May 2014
Posts: 592
Given Kudos: 0
GRE 1: Q165 V161
Re: number system
[#permalink]
08 May 2016, 02:42
08 May 2016, 02:42
Expert Reply
Exaplanation
Choose the number which is just greater than 200 and divisible by 13. That will be 208.
Similarily, find the number which is just less than 600 and divisible by 13. (Remainder(600,13) = 2). Therefore it is 598.
Therefore, the total numbers of numbers which are divisible by 13 and between 200 and 600 are:
(598-208)/13 + 1 = 390/13+ 1 = 31.
