1. The problem statement, all variables and given/known data Let X1,X2,...,Xn be positive real numbers. Show that ((x15+...+xn5 )/ n)1/5 >= ((x14+...+xn4 )/ n)1/4 2. Relevant equations 3. The attempt at a solution I have tried by taking logarithms. Is it right approach? Or.. It can be applied to AM-GM-HM inequality? how?