Answer:
Length = 18 inches
Width = 9 inches
Explanation:
Since the length is 6 inches and it is on a scale of 1:15, by multiplying 6 by 15 you get the intended length of the lawn.
 inches
 inches
Do the same for the width
 inches
 inches
Then divide both values by 5 since the new scale factor is 1:5
This gives you 18 inches for the length and 9 for the width.
Hope this helps :)