Respuesta :
Answer:
7.5 Hours
Step-by-step explanation:
(18 pages per hour) * (x hours) = (135 pages)
18x pages = 135 pages
18x = 135
Divide both sides by 18 to get rid of the 18 and to get x on its own.
x = 135 / 18
x = 7.5
Mary would take 7.5 hours to complete the book.