Answer:
Step-by-step explanation:
19.9% = 19.9/100 = 0.199
80.1% = 80.1/100 = 0.801
0.199 * 10.0129371 = 1.992574483
0.801 * 11.0093055 = 8.818453706
Mass = 10.81102819
This should be rounded to six places after the decimal. 10.811028 if the given amu's are used.
If the %s are used, then 10.811 is the best answer.