Perimeter is adding all 4 sides of a rectangle together.
Since the length is 1-1/2 yards longer than it's width, 2 sides are 1-1/2 yards longer.
So now we know that 2 sides are: 1-1/2 + 1-1/2 = 3 yards longer.
Subtract the 3 yards from the perimeter: 40 -3 = 37 yards.
To find the width, divide 37 yards by 4 sides: 37 / 4 = 9-1/4 yards.
The width is 9-1/4 yards.
The length is the width plus 1-1/2: 9-1/4 + 1-1/2 = 10-3/4 yards.
Check to see if this equals the perimeter: 10-3/4 + 10-3/4 + 9-1/4 + 9-1/4 = 40 yards.
That works out so we now have the length and width.
Area = Length x width
Area = 9-1/4 x 10-3/4 = 99 7/16 square yards.