The width of a rectangular hall is ½ of its length. If the area of the hall is 578 sq.m, what is the difference between its length and breadth?	Pick one
A) 8 m
B) 10 m
C) 12 m
D) 15 m
E) 17 m

Rationale: "let the length of the hall be x m breadth of the hall = 1 x / 2 m area of the hall = length * breadth 578 = x * 1 x / 2 x ² = 1156 x = 34 difference between the length and breadth of the hall = x - 1 x / 2 = x / 2 = 34 / 2 = 17 m answer : e"
Answer: E