The roof of an apartment building is rectangular and its length is 3 times longer than its width. If the area of the roof is 768 feet squared, what is the difference between the length and the width of the roof?  Select:
A) 32. B) 40. C) 42. D) 44. E) 46.
Answer is A : 42   Let w be the width , so length is 3w. Therefore : w*4w = 768, solving for, w = 16 , so 3w-w = 2w = 2*16= 
<gadget id="calculator">2*16</gadget>
<output>32</output>
32
<result>A</result>
The roof of an apartment building is rectangular and its length is 3 times longer than its width. If the area of the roof is 768 feet squared, what is the difference between the length and the width of the roof?