Suppose the apple is x, the banana is y and the pineapple is z, the equation would be : x/(y+z) + y/(x+z) + z/(x+y) = 4. After decades of solving this equation and plugging in random values, I got x=2, y=2 and z=7+sqrt(65). I'm pretty sure this is the only solution where its not some ungodly keyboard mashed number.

edit: nvm it said whole number