.
All possible opportunities are listed in the table below (two most-left columns)
#of fiction books #of non-fiction books #of combinations value
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1 4 882
2 3 1764
3 2 1260
4 1 315
The third column contains the formulas for the number of selections.
The fourth column contains the values calculated with these formulas:
= = 882;
= = 1764;
= = 1260;
= = 315.
Now your last step is to add all four numbers in the right column: 882 + 1764 + 1260 + 315 = 4221.
Answer. The selection of books can be made in 4221 ways.