We’re given the following values:

X-54: Mass = **53.93961 amu** f.a. = 5.845 % ÷ 100 = **0.05845**

X-56: Mass = **55.93494**** amu** f.a. = 91.75 % ÷ 100 = **0.91750**

X-57: Mass = **56.93539 amu ** f.a. = 2.123 % ÷ 100 = **0.02123**

X-57: Mass = **57.93328 amu ** f.a. = 0.2820% ÷ 100 = **0.00282**

Average Atomic Mass = **??**

A certain element X has four isotopes.

• 5.845% of X has a mass of 53.93961 amu.

• 91.75% of X has a mass of 55.93494 amu.

• 2.123% of X has a mass of 56.93539 amu.

• 0.2820% of X has a mass of 57.93328 amu.

What is the average atomic mass of element X?

Express your answer numerically to four significant figures.

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