There is a sequence an such that a1=1,a2=2,a3=3, and an+3=
an+2-an+1+an, then a10=?
A 0
B. 1
C. 2
D. 3
E. 4
C
an+2-an+1+an, then a10=?
A 0
B. 1
C. 2
D. 3
E. 4
C
Hi Shazi1711,
This sequence question is really just about staying organized and doing some basic arithmetic. We're told that...
1st term = 1
2nd term = 2
3rd term = 3
And every term AFTER the third term follows the following pattern: each term equals "one term back" - "two terms back" + "three terms back"; so...
4th term = 3 - 2 + 1 = 2
5th term = 2 - 3 + 2 = 1
6th term = 1 - 2 + 3 = 2
7th term = 2 - 1 + 2 = 3
8th term = 3 - 2 + 1 = 2
9th term = 2 - 3 + 2 = 1
10th term = 1 - 2 + 3 = 2
Final Answer: C
GMAT assassins aren't born, they're made,
Rich
