A metal alloy weighing 4 kg and
containing 90% gold is melted and mixed
with 1 kg of a different alloy which
contains 30% gold. What percent of the
resulting alloy is gold?
A) 78% B) 90%
C) 32% D) 50%

The ages of personnel in the accounting department of a large company are normally distributed with a standard deviation of 7 years. there is a 0.02275 probability that the age of any randomly chosen person in the department is less than 22 and 0.15866 probabilty that the age of any randomly chosen person is greater than 43. what is the mean of this distribution?