Final answer:
To determine the combined thickness of the two pieces of wood, we add 2 1/2 inches (converted to 5/2 inches) to 1/5 inch, resulting in a total thickness of 27/10 inches, which is 2.7 inches.
Step-by-step explanation:
Isabelle takes a piece of wood that is 2 1/2 inches thick and glues it to a piece of wood that is 1/5 of an inch thick. To find the total thickness, we add the two measurements together. We first convert 2 1/2 inches to an improper fraction to make the addition easier. 2 1/2 inches is the same as 5/2 inches. Now we add 5/2 inches to 1/5 inch.
5/2 + 1/5 = (5 * 5)/(2 * 5) + (1 * 2)/(5 * 2) = 25/10 + 2/10 = 27/10 inches, which is equal to 2.7 inches. So, the combined thickness of the two pieces of wood is 2.7 inches.