In a bookcase, there are 4 fiction books for every 9 nonfiction books. there are 78 books in the bookcase. how many fiction books are in the bookcase?

Which speed is the fastest (use 1 mile ≈ 1.6 kilometers)? a. 12 miles/hour b. 18 feet/second c. 19 kilometers/hour d. cannot be determined

Gabriel determined that his total cost would be represented by 2.5x + 2y – 2. his sister states that the expression should be x + x + 0.5x + y + y – 2. who is correct? explain.

In the equation sqrt(n+5)-sqrt(11-10)=1. what is the value of n