For a given chemical reaction γ1A + γ2B → γ3C + γ4D Concentration of C changes form 10 mmol dm-3 to 20 mmol dm-3 in 10 seconds. Rate of appearance of D is 1.5 times the rate of disappearance of B which is twice the rate of disappearance A. The rate of appearance of D has been experimentally determined to be 9 mmol dm-3s-1. Therefor the rate of reaction is______mmol dm-3s-1. (Nearest Integer)