John has finished planting 1/4th of the area of rectangular garden which is 12ft wide. When he finishes planting another 90 sq. ft of the garden, he would have finished 2/5th of the area. What is the length of the garden?
Let the area of the garden be ‘x’ sq. ft, then the difference between 2/5 and 1/4 of the area is 90 sq. ft, ⇒ (2/5- 1/4) × x = 96 ⇒ 3/20 x = 90 sq. ft ⇒ x = (90 × 20)/3 = 600 ∴ Length = Area/Width = 600/12 = 50 ft.
