A certain element is composed of two isotopes, having the ma…

A certain element is composed of two isotopes, having the mass and abundance shown below.  What is the average atomic mass unit (amu) for this element?   Mass Abundance Isotope 1: 35.0 amu 75.8% Isotope 2: 37.0 amu 24.2% (Hint: Atomic mass = Σ(mass of isotope)(abundance of isotope))