Answer:
11/20
Step-by-step explanation:
The backyard is 1 entire area.
The pool is 1/5 of the area.
The deck is 1/4 of the area.
The grass is the remaining area.
The area of the grass is the entire area of the backyard minus the areas of the pool and the deck.
First, we add the areas of the pool and the deck.
1/4 + 1/5 = 5/20 + 4/20 = 9/20
The combined area of the pool and deck is 9/20 of the area of the backyard.
Now we subtract the combined area of the pool and deck from the entire area of the backyard.
1 - 9/20 = 20/20 - 9/20 = 11/20
The grassy area is 11/20 of the backyard.
Answer: 11/20