The area of the garden be after he doubles the length and width is 160 square feet.
Given that,
Based on the above information, the calculation is as follows:
We know that
Area = (length) (width)
Now if the area is doubled
So,
= (2) (length) (2) (width)
= 4(length) (width)
= 4 (40)
= 160
Therefore, we can conclude that option b is correct.
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