Length of a cuboid is 6 m more than its breadth while its height is 25% more than its breadth. Volume of cuboid is 3240 m3. Find its total surface area? [Length, breadth and height is integer]
- AOption (a)
1332
- BOption (b)
2453
- COption (c)
4532
- DOption (d)
1472
- EOption (e)
1892
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Correct answer
1332
Why this answer is correct
Calculation
Breadth = 4x
Length = 4x + 6
Height = 25% more than breadth = 4x + [25/100] × 4x = 4x + x=5x
Volume=Length × Breadth × Height =
Or, (4x + 6)(4x)(5x) =3240
(4x + 6)(4x)(5x) = 3240
⇒ (4x + 6) x2 = 162
Or, 4x3 + 6x2 = 162
Try x =1,2,3…. [All value is integer]
108 + 54 = 162 [x = 3]
Breadth = 4x = 12 m
Length = 4x + 6 = 18 m
Height = 5x = 15 m
TSA = 2(lb + bh + hl)
= 2[(18 × 12) + (12 × 15) + (15 × 18)]
= 2(216 + 180 + 270) = 2 × 666 = 1332 m²