The charge for a single room at Hotel P is 20 percent less than the charge for a single room at Hotel R and 10 percent less than the charge for a single room at Hotel G. The charge for a single room at Hotel R is what percent greater than the charge for a single room at Hotel G ?  Choose the correct option:
A) 15 %	B) 20 %	C) 12.5 %	D) 50 %	E) 150 %

Rationale: "let rate in r = 100 x then p = 80 x g = 100 y p = 90 y thus 80 x = 90 y or x = 1.125 y ans r = 112.5 y so increase = 12.5 % answer : c"
Answer: C