Question

the area of a rectangular hall is 165sq.m. If its length is 4m more than its breadth what is the length and breadth of the hall?

Answer 1

area = length * breadth
165 = (b+4)(b)                                        [area= 165 (given)  & length is 4 more    165 = b²+4b                                                                               than its breadth]
 0 = b²+4b-165
0 = b² + 15b - 4b -165
0 = b(b-15) + 4(b-15)
0 = (b-15)(b+4)
b = -4               [rejected as length can't be -ve]
    or
b = 15
Hence breadth = 15 cm
and length = 15 +4 =19 cm

Answer 2

let length = x
breadth = 2x
area of rectangle = l*b
according to the sum 
            x * 2x = 165
              3x = 165
                x = 165/3
                x = 55
lenght = 55
bradth == 55*2= 110