Question

plz help im gonna cry.....
word problem frenzy!
mrs. haye is planning to place a layer of landscaping rock 1/2 foot deep around the three sides of the patio along the back of her house. the patio is 18ft by 10ft. she plans to have rock extend 2ft out form the longer side of the patio. she intends to use 60 cubic ft of the rock because that is how much she can haul in her truck. how wide can she extend the rock out from the other two sides of the patio???
answer choices
a. 4 1/2ft
b. 4ft
c. 3 1/2ft
d. 3ft