Answer: B. length=12, width=18
Explanation:
Let x = Length of the playground then width = x+6
Area of a rectangular playground = Length x width
Since , area of playground =

Then , we have

But length cannot be negative , so reject x= -18 .
Thus , the length of playground = 12 yd
Then , width = 12+6 = 18 yd
Hence, the correct answer is B. length=12, width=18