Ralph bought 4 books for k dollars each. Iris bought 5 books for k dollars each. If together they spend 90 dollars, how much is each book? 4k+5k=90 so 9k=90 90/9=10 so $10 each
correct
To find the cost of each book, we need to solve the equation:
4k + 5k = 90
First, let's simplify the equation by combining like terms:
9k = 90
To isolate k, divide both sides of the equation by 9:
k = 90 / 9
Simplifying the right side gives us:
k = 10
Therefore, each book costs $10.