Alphonso bought several books. The cost of each book was `$9.79`, `$22.57`, `$17.74`, `$10.80`, and `$25.49`. What is the mean price of the books Alphonso bought?
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Box 1: Enter your answer as an integer or decimal number. Examples: 3, -4, 5.5172 Enter DNE for Does Not Exist, oo for Infinity