EduGoog

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.

Option:
A. 40 cm
B. 60 cm
C. 80 cm
D. 120 cm
Answer: A . 40 cm

Justification:

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

Next