Im stuck on this problem Please help?

You hypothesize that you have discovered a new element. To test this hypothesis, you obtain a m spectrometry ysis of the sample and discover that it contains three isotopes with mes of 270.51 amu, 271.23 amu, and 269.14 amu and relative abundances of 34.07%, 55.12%, and 10.81%, respectively. Based upon this, the average atomic m of the element is?