The Average Daily Food Consumption F of a Herbivorous Mammal $F = 0.4 x ^ { 3 / 4 }$

Short Answer

The average daily food consumption F of a herbivorous mammal with body weight x, where both F and x are measured in pounds, is given approximately by the equation $F = 0.4 x ^ { 3 / 4 }$
. Find the weight x of an elephant that consumes 400 lb of food per day.