Each gram of mammalian skeletal muscle consumes ATP at a rate of about 1.0103mol/min during contraction. To bridge the short interval between the moderate demand for ATP met by aerobic metabolism and the high demand met by anaerobic ATP production, muscles carry a small reserve of the compound creatine phosphate which, due to its high phosphoryl group transfer potential (see the figure on the left), is capable of phosphorylating A.DP very efficiently. The reaction is catalyzed by the enzyme creatine kinase: Creatine phosphate Creatine Because the equilibrium lies well to the right, virtually all of the muscle ADP or AMP is converted to ATP as long as creatine phosphate is available. Concentrations of ATP and creatine phosphate in muscle are about 2.0mM and 23mM, respectively, and the density of muscle tissue can be taken to be about 1.2g/cm3. How long could contraction continue using ATP alone? Express your answer to two significant figures and include the appropriate units