A rectangle has the length doubled to its width. If the width is increased by 5 cm and the length is decreased by 5cm, then the new area is increased by 75 Sq. cm. Find the original length of the rectangle.
Original length of the rectange is L.
Original width of the rectange is B.
=> L = 2B.
Area A = L * B = 2 * B^2.
New area of the rectange N = (L-5) * (B+5) = A - 5B +5L - 25 = A + 75
=> 5 (L -B) = 100
=> 5 (2*B - B) = 100
=> B = 20
=> L = 40 cm