Answer:
He is incorrect. The path will have an area of (4)(40) = 160 ft². The yard has an area of 600 ft². The area of the lawn will be the difference of the yard and path, so it is 440 ft².
Explanation:
1. Original area of yard
A = lw = 40 × 15 = 600 ft²
2. Area of path
The path is a parallelogram.
A = bh = 4 × 40 =160 ft²
3. Remaining area
Remaining area = original area - area of path = 600 - 160 = 440 ft².