There is a square field whose side is 44m. A square flower bed is prepared in its centre leaving a gravel path all round the flower bed. The total cost of laying the flower bed and gravelling the path at Rs. 2.75 and Rs. 1.50 per square metre, respectively, is Rs 4904. Find the width of the gravel path.
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Let the width of the gravel path be x m.
Each Sides of the square flower bed = (44 - 2x) m.
Area of the square field= side × side
Area of the square field= 44× 44 = 1936 m²
Area of flower bed = (44-2x)² = 1936 -176x+4x²
Area of the gravel path = area of the square field - area of the flower bed
= 1936 - (1936 - 176x + 4x²)
= 1936 - 1936 + 176x - 4x²
= 176 x - 4x²
Cost of laying the flower bed =( Area of the flower bed) × ( rate per square metre)
= (44-2x)² × 2.75
=( 275/100)(44-2x)²
= 11/4 × (44-2x) (44-2x)
= 11/4 ×2 (22 -x) 2 (22 -x)
= 11/4 ×4 (22 -x)²
= 11(22-x)²
Cost of graveling the path =( Area of the path) × ( rate per square metre)
= (176x - 4x²) × 150/100
= 4 (44x -x²) × 3/2
= 4 × 3/2 × (44x -x²)
= 6× (44x -x²)
Given = the total cost of laying the flower bed and gravelling the path is ₹ 4904.
11(22-x)² + 6× (44x -x²) = 4904
= 11(484 - 44 x +x²) + (264x - 6x²)= 4904
= 11(484 - 44 x +x²) +6 (44x - x²)= 4904
= 5x² -220x + 5234 = 4908
= 5x² -220x +420 = 0
= x² - 44x +84= 0
= x² -42x -2x +84=0
= x( x-42) -2(x-42)=0
= (x-2) (x-42)= 0
= x= 2 or x= 42
But x≠42, as the side of the square is 44 m. Therefore x= 2
Hence, the width of the gravel path is 2 m.
HOPE THIS WILL HELP YOU..
Each Sides of the square flower bed = (44 - 2x) m.
Area of the square field= side × side
Area of the square field= 44× 44 = 1936 m²
Area of flower bed = (44-2x)² = 1936 -176x+4x²
Area of the gravel path = area of the square field - area of the flower bed
= 1936 - (1936 - 176x + 4x²)
= 1936 - 1936 + 176x - 4x²
= 176 x - 4x²
Cost of laying the flower bed =( Area of the flower bed) × ( rate per square metre)
= (44-2x)² × 2.75
=( 275/100)(44-2x)²
= 11/4 × (44-2x) (44-2x)
= 11/4 ×2 (22 -x) 2 (22 -x)
= 11/4 ×4 (22 -x)²
= 11(22-x)²
Cost of graveling the path =( Area of the path) × ( rate per square metre)
= (176x - 4x²) × 150/100
= 4 (44x -x²) × 3/2
= 4 × 3/2 × (44x -x²)
= 6× (44x -x²)
Given = the total cost of laying the flower bed and gravelling the path is ₹ 4904.
11(22-x)² + 6× (44x -x²) = 4904
= 11(484 - 44 x +x²) + (264x - 6x²)= 4904
= 11(484 - 44 x +x²) +6 (44x - x²)= 4904
= 5x² -220x + 5234 = 4908
= 5x² -220x +420 = 0
= x² - 44x +84= 0
= x² -42x -2x +84=0
= x( x-42) -2(x-42)=0
= (x-2) (x-42)= 0
= x= 2 or x= 42
But x≠42, as the side of the square is 44 m. Therefore x= 2
Hence, the width of the gravel path is 2 m.
HOPE THIS WILL HELP YOU..
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