(a) What is the efficiency of an out-of-condition professor who does 1.90 x 10" J of useful work while metabolizing 490 kcal of food energy? (Enter your answer as a percentage. Enter a number.) % (b) .. How.many. food calories (in kcal) would a well-conditioned athlete metabolize in doing the same work with an efficiency of 20%? (Enter a number.) Ex kcal Enter a number. + Submit