Find the average atomic mass for B if 19.9% of B atoms are 10B with a mass of 10.0129371 amu and 80.1% are 11B with a mass of 11.0093055 amu

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.

i believe the answer is 5,000