Problem: Two short-lived isotopes of an element are produced in a nuclear reaction. One of these isotopes has a mass of 5.3731 amu and accounts for 85.5% of the production. The remaining other isotope has a mass of 7.3904 amu. Use this information to calculate the atomic mass of this element.
Only enter your numerical answer below - do not include units. Report your answer to 2 decimal places.