GRE 9367 Q36

[nomis]

I think this one should be an easier one, but I can't seem to figure it out.

36. If F is a function such that, for all positive integers x and y F(x,1)=x+1, F(1,y)=2y, and F(x+1, y+1) = F( F(x, y+1), y), then F(2,2) =
a) 8
b) 7
c) 6
d) 5
e) 4

correct answer is D.

Thanks for your responses.

[berkbelt]

F(2,2) = F(1+1,1+1) = F(F(1,1+1),1) = F(F(1,2),1) = F(4,1) = 5.

[nomis]

AH. Perfect. Thanks again.