Core Logic
Let the time taken by mason A alone to complete the work be x$x$ days.
Mason B takes x + 24$x + 24$ days.
Work done by A in 1 day = (1)/(x)$\frac{1}{x}$
Work done by B in 1 day = (1)/(x + 24)$\frac{1}{x + 24}$
Step 1: Set up the Rate Equation
Since together they finish in 22.5$22.5$ days, their combined work in 1$1$ day is (1)/(22.5) = (1)/(45/2) = (2)/(45)$\frac{1}{22.5} = \frac{1}{45/2} = \frac{2}{45}$.
So, (1)/(x) + (1)/(x + 24) = (2)/(45)$\frac{1}{x} + \frac{1}{x + 24} = \frac{2}{45}$
Step 2: Solve the Quadratic
Multiply to clear denominators:
(x + 24 + x)/(x(x + 24)) = (2)/(45)$$\frac{x + 24 + x}{x(x + 24)} = \frac{2}{45}$$
45(2x + 24) = 2(x² + 24x)$$45(2x + 24) = 2(x^2 + 24x)$$
90x + 1080 = 2x² + 48x$$90x + 1080 = 2x^2 + 48x$$
2x² - 42x - 1080 = 0$$2x^2 - 42x - 1080 = 0$$
x² - 21x - 540 = 0$$x^2 - 21x - 540 = 0$$
Factorizing:
(x - 36)(x + 15) = 0$$(x - 36)(x + 15) = 0$$
Since time cannot be negative, we reject x = -15$x = -15$.
So, x = 36$x = 36$ days.
Pattern Recognition
Standard "Time & Work" reciprocal addition resolves purely to a clean factorizable quadratic. Setting the faster worker to x$x$ prevents dealing with negative bounds in factors.
Chapter Mix
Class 11 Maths: Basic Mathematics