BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

average of new sequence

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 194
Joined: Mon Oct 15, 2012 7:14 pm
Location: India
Thanked: 47 times
Followed by:6 members

by The Iceman » Sat Feb 09, 2013 12:07 pm
Even multiples of 5 are basically multiples of 10. So, these numbers are 20,30,40,...100

The new sequence has the following numbers: 60,90,120...300

Since these numbers are evenly spaced, average of these numbers = (60+300)/2 = 180
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3380
Joined: Mon Mar 03, 2008 1:20 am
Thanked: 2256 times
Followed by:1535 members
GMAT Score:800

by lunarpower » Wed Feb 13, 2013 9:27 am
that works.

since you're multiplying everything by 3, you can just find the average of the original (smaller) set and then track what happens to that quantity.
everything is evenly spaced, so the average of the set 20, 30, 40, ..., 100 is the middle number, which is 60. (if you have trouble seeing that this is the middle number, just write out all the numbers; it takes less than 10 seconds.)

so, the new average will be 3 times that middle number, or 180.
Ron has been teaching various standardized tests for 20 years.

--

Pueden hacerle preguntas a Ron en castellano
Potete chiedere domande a Ron in italiano
On peut poser des questions à Ron en français
Voit esittää kysymyksiä Ron:lle myös suomeksi

--

Quand on se sent bien dans un vêtement, tout peut arriver. Un bon vêtement, c'est un passeport pour le bonheur.

Yves Saint-Laurent

--

Learn more about ron
Top
Post new topic Post Reply
• Page 1 of 1