Data Sufficiency

PLEASE ELABORATE ANSWER??

From 1 c = 9 R = 8

From 2 we get the same thing ...c +c -1 = 17 ...c = 9 so r = 8

Hence D

sujaysolanki, I am agree with u but would like to add something more -
By stmt - 1, R = C - 1 and RC = 72
So C(C - 1) = 72 From this we get C = 8 or 9. If C = 8, R = 7 - which does not match; so discard it. But if c = 9, R = 8 - accept it.
By stmt - 2, we are getting last 2 rows having 18 chairs. so each row = 9 chairs.
Got it, URK.NET?

thnks missed that out