The roof of an apartment building is rectangular and its length is 7 times longer than its width. If the area of the roof is 847 feet squared, what is the difference between the length and the width of the roof?  Choose the most appropriate option:
A) 38.
B) 40.
C) 66.
D) 44.
E) 46.
Answer is C : 66   Let w be the width , so length is 7w. Therefore : w*7w = 847, solving for, w = 11 , so 7w-w =6w = 6*11= 
<gadget id="calculator">6*11</gadget>
<output>66</output>
66
<result>C</result>
The roof of an apartment building is rectangular and its length is 7 times longer than its width. If the area of the roof is 847 feet squared, what is the difference between the length and the width of the roof?