+2 votes
in Class 9 by kratos

The dimensions of a rectangular box are in the ratio of 2: 3: 4 and the difference between the cost of covering it with sheet of paper at the rates of Rs 8 and Rs 9.50 per m2 is Rs 1248. Find the dimensions of the box.

1 Answer

+3 votes
by kratos
 
Best answer

Given details are,

Ratio of dimensions of rectangular box = 2:3:4

Let length of box be ‘2x’ m

Let breadth of box be ‘3x’ m

Let height of box be ‘4x’ m

Area of sheet of paper required for covering it = total surface area of cuboid

= 2 (lb+bh+hl)

= 2 (2x×3x + 3x×4x + 4x×2x)

= 2 (6x2 + 12x2 + 8x2)

= 2 (26x2)

= 52 x2 m2

Cost for covering with sheet of paper at the rate of Rs 9.50 /m2= 52x2 × 9.50

= Rs 494x2

Cost for covering with sheet of paper at the rate of Rs 8 /m2 = 52x2 × 8

= Rs 416x2

Given, the difference between the cost of covering it with sheet of paper at the rates of Rs 8 and Rs 9.50 per m2 is Rs 1248

494x2 – 416x2 = 12448

78x2 = 1248

x2 = 1248/78

= 16

x = √16

= 4

∴ Length of box = 2x = 2×4 = 8m

Breadth of box = 3x = 3×4 = 12m

Height of box = 4x = 4×4 = 16m

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