WAEC Mathematics 2024 Paper

Concept:The perimeter of a rectangle is twice the sum of its length and width.Use the given relation between length and width to form an equation.Explanation:Let the length of the garden be $x$ metres.The width is 7 m less than the length, so width $= x - 7$.Perimeter of a rectangle $= 2(\text{length} + \text{width})$.Given perimeter $= 90$ m, we write:$$2(x + x - 7) = 90$$$$2(2x - 7) = 90$$Divide both sides by 2:$$2x - 7 = 45$$Add 7 to both sides:$$2x = 52$$Divide by 2:$$x = 26$$Thus, the length of the garden is 26 m.Answer:The length of the garden is $26$ m.Correct option: D.