Events & Promotions
|
|
GMAT 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.
Sep 1507:00 PM EDT
-09:00 PM EST
Elite scores are possible when you enroll in a powerful GMAT course, taught live online + 6 months access to TTP OnDemand video courses included! Class starts Tues/Thurs Sept. 15, 2026 - Nov. 15, 2027, 7:00pm-9:00pm EST
Sep 2107:00 PM EDT
-10:00 PM EDT
Boost your GMAT score in less than one month in a live online class + 6 months access to TTP OnDemand video courses included! Class starts Mon, Tues, Wed, Thur, Fri Sept. 21, 2026 - Oct. 9, 2027, 7:00pm-10:00pm EST
04 Aug 2020, 02:31
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
55%
(hard)
Question Stats:
64% (02:02) correct
36%
(02:35)
wrong
based on 315
sessions
History
Date
Time
Result
Not Attempted Yet
[GMAT math practice question]
What is the value of \(\frac{2}{3·5} + \frac{2}{5·7} + \frac{2}{7·9} + \frac{2}{9·11} + \frac{2}{11·13}\)?
A. \(\frac{2}{27}\)
B. \(\frac{3}{29}\)
C. \(\frac{5}{33}\)
D. \(\frac{9}{37 }\)
E. \(\frac{10}{39} \)
What is the value of \(\frac{2}{3·5} + \frac{2}{5·7} + \frac{2}{7·9} + \frac{2}{9·11} + \frac{2}{11·13}\)?
A. \(\frac{2}{27}\)
B. \(\frac{3}{29}\)
C. \(\frac{5}{33}\)
D. \(\frac{9}{37 }\)
E. \(\frac{10}{39} \)
Thelegend2631
Posts: 371
Updated on: 07 Aug 2020, 03:24
Originally posted by Thelegend2631 on 04 Aug 2020, 05:30.
Last edited by Thelegend2631 on 07 Aug 2020, 03:24, edited 3 times in total.
Last edited by Thelegend2631 on 07 Aug 2020, 03:24, edited 3 times in total.
Kudos
Bookmarks
Try this way
1/3-1/5 = 2/15 = 2/3.5
That means,
Y =(1/3-1/5)+(1/5-1/7)+(1/7-1/9)+(1/9-1/11)+(1/11-1/13)
=1/3-1/13
=(13-3)/39
= 10/39
Posted from my mobile device
1/3-1/5 = 2/15 = 2/3.5
That means,
Y =(1/3-1/5)+(1/5-1/7)+(1/7-1/9)+(1/9-1/11)+(1/11-1/13)
=1/3-1/13
=(13-3)/39
= 10/39
Posted from my mobile device
06 Aug 2020, 03:44
Kudos
Bookmarks
=>
Remember that \(\frac{2}{n(n + 2)} = \frac{1}{n} – \frac{1}{n + 2}.\)
\(\frac{2}{3·5} + \frac{2}{5·7 }+ \frac{2}{7·9} + \frac{2}{9·11} + \frac{2}{11·13}\)
\(= (\frac{1}{3} – \frac{1}{5}) + (\frac{1}{5} – \frac{1}{7}) + (\frac{1}{7} – \frac{1}{9}) + (\frac{1}{9} – \frac{1}{11}) + (\frac{1}{11} – \frac{1}{13})\)
\(= \frac{1}{3} – \frac{1}{13}\)
\(= \frac{(13 - 3)}{(3·13)} = \frac{10}{39}\)
Therefore, E is the correct answer
Answer: E.
Remember that \(\frac{2}{n(n + 2)} = \frac{1}{n} – \frac{1}{n + 2}.\)
\(\frac{2}{3·5} + \frac{2}{5·7 }+ \frac{2}{7·9} + \frac{2}{9·11} + \frac{2}{11·13}\)
\(= (\frac{1}{3} – \frac{1}{5}) + (\frac{1}{5} – \frac{1}{7}) + (\frac{1}{7} – \frac{1}{9}) + (\frac{1}{9} – \frac{1}{11}) + (\frac{1}{11} – \frac{1}{13})\)
\(= \frac{1}{3} – \frac{1}{13}\)
\(= \frac{(13 - 3)}{(3·13)} = \frac{10}{39}\)
Therefore, E is the correct answer
Answer: E.
