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

Redeem

Averages logic help!!

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 46
Joined: Wed Mar 10, 2010 8:54 am
Followed by:1 members

Averages logic help!!

by CaptainM » Fri Nov 12, 2010 11:53 am
One doubt:

If the Qs says:
What is the average of five nos?
(1) the average of first three is 5(any number) and last 3 is 9(any number)
(2) the average of first 3 is 7 and last 2 is 8

These nos are random so plz don't calculate...just the logic plzz :)
Top
Source: — Data Sufficiency |
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Wed Dec 16, 2009 10:12 am

by ajayrkp » Fri Nov 12, 2010 1:07 pm
Let's say we have five numbers n1, n2, n3, n4, n5

(1) Firstly, "(any number)" is confusing to me. I am not sure what it means here. However, if we take average of first 3 numbers [(n1+n2+n3)/3 = 5] and last 3 as [(n3+n4+n5)/3 = 9], we can not determine value of avg of all five number. Therefore, INSUFFICIENT.

(2) avg of first three number [(n1+n2+n3)/3 = 7] and last 2 is [(n4+n5)/2 = 8], we would be able to calculate [(n1+n2+n3+n4_n5)/5 = 37/5] by adding first two equations. So SUFFICIENT.

Answer should be B
Top
Post new topic Post Reply
• Page 1 of 1