Answer:
The answer is given below
Explanation:
The question is not complete because it does not contain the line plot. A line plot is attached and steps on how to calculate.
From the line plot, if Maria stacked the books that were 3/4 inches thick on top of the books that were 1 inches thick, the result would be as follows.
A line plot shows the frequency of data using a number line. As seen from the line plot, 5 books are 3/4 inches thick and 4 books are 1 inches thick. If the 1 inches thick books was stacked on the 3/4 inches thick book, the resulting thickness would be:

Therefore Maria pile of books as a result of stacking 3/4 inches thick on top of the books that were 1 inches thick = 7.75 inches