Some of the scientists in the lab decided to see what would happen if they took two different mixtures and mixed them together. They called this the "union" of the two mixtures. For example, in Problem B4, they took the two mixtures A and B and formed the union of the mixtures. Standard mathematical notation for the union of two things (usually sets) is U, so they named their new mixture A U B.
Mixture A has a BQ of 1/3, and the lab has decided that it would like A U B to have a BQ of 1/2. What could be the BQ of mixture B? Is there more than one answer? Why?