If an+2=an+an+1

This topic has expert replies
Junior | Next Rank: 30 Posts
Posts: 23
Joined: Tue Nov 11, 2008 6:46 am

If an+2=an+an+1

by mmgmat2008 » Fri Dec 05, 2008 5:23 am
(n>=1), what is a6?

(1)a6-a5=3
(2)a7+a8=34

The answer is c. I don't know how to look at statement (2)

Legendary Member
Posts: 891
Joined: Sat Aug 16, 2008 4:21 am
Thanked: 27 times
Followed by:1 members
GMAT Score:660(

by 4meonly » Fri Dec 05, 2008 6:19 am
n>=1), what is a6?

(1)a6-a5=3
(2)a7+a8=34

(1)
means that succesive term is 3 greater than preceding. It is difference between neighbouring terms
UNSUFF to find the value of a6

(2)
Sum of neighbouring terms
UNSUFF to find the value of a6

(1)(2)
a6 + 3 = a7
a6 + 3 + 3 = a8
2*a6 + 9 = 34

a6 can easily be found

C

Junior | Next Rank: 30 Posts
Posts: 23
Joined: Tue Nov 11, 2008 6:46 am

thanks

by mmgmat2008 » Fri Dec 05, 2008 4:49 pm
It is a new type of question, I get it now.

thanks.