There are 7 identical pens and 9 identical books. In how many different ways can a person select at least one object from this set? Choose the correct choice from the following choices.
A) 16 B) 31 C) 48 D) 79 E) 90
We can select from 0 to 7 pens and from 0 to 9 books.   Thus the total possible ways to select objects is   8*10= 
<gadget id="calculator">  8*10</gadget>
<output>80</output>
80   We must subtract 1 for the case with 0 pens and 0 books.   The answer is 79.
<result>D</result>
There are 7 identical pens and 9 identical books. In how many different ways can a person select at least one object from this set?