Coruja wrote:

The average (arithmetic mean) cost per book for the 12 books on a certain table is k dollars. If a book that costs 18 dollars is removed from the table and replaced by a book that costs 42 dollars, then in terms of k, what will be the average cost per book, in dollars, for the books in the table?

A) k+2

B) k - 2

C) 12+ 24/k

D) 12- 24/k

E) 12k-6

**Quote:**

he average (arithmetic mean) cost per book for the 12 books on a certain table is k dollars.

Total cost of 12 books = 12k

**Quote:**

If a book that costs 18 dollars is removed from the table and replaced by a book that costs 42 dollars

Total cost of books now = 12k - 18 + 42 Or, 12k +24

**Quote:**

what will be the average cost per book, in dollars, for the books in the table

Average cost will be \(\frac{(12k + 24 )}{24}\) = k + 2

Hence answer will be (A) k + 2
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Thanks and Regards

Abhishek....

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