There are two boxes on a table. Box A contains three balls
labeled A1, A2, and A3. Box B contains four balls labeled B1, B2,
B3, and B4. An experiment consists of selecting one ball from each
box at random and observing their numbers; e.g. if A3 is drawn, the
corresponding number is 3. (a) What is the sample space of this
experiment? Write the event E = “the sum of the numbers is 5” as a
subset of the sample space.