Data Sufficiency

(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)

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

It is a new type of question, I get it now.

thanks.