In a rectangular plot of dimensions 60 m × 35 m, four houses (shaded region) were built leaving pathways, as shown in the figure given below. If area of shaded region is 36% of the area of rectangular park, then find the value of x. 

In a rectangular plot of dimensions 60 m × 35 m, four houses (shaded region) were built leaving pathways, as shown in the figure given below. If area of shaded region is 36% of the area of rectangular park, then find the value of x.  Correct Answer 8 m

Given:

Formula used:

Area of rectangle = length × breadth

Calculation:

Area of rectangular plot = 60 × 35 = 2100 m2 

When the houses are built, 

⇒ Length of shaded region = (60 – 4x) m 

⇒ Breadth of shaded region = (35 – x) m 

⇒ Area of shaded region = (60 – 4x) (35 – x) = (2100 – 200x + 4x2

Now, area of shaded region = 36% of Area of rectangular plot 

⇒ (2100 – 200x + 4x2) = 36% of 2100 

⇒ 2100 – 200x + 4x2 = 756 

⇒ 4x2 – 200x + 1344 = 0 

⇒ x2 – 50x + 336 = 0 

⇒ x2 – 8x – 42x + 336 = 0 

⇒ (x – 8) (x – 42) = 0 

⇒ x = 8, 42 

∵ The value of ‘x’ cannot be greater than the breadth of park 

∴ x = 8 m 

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