Question

Find the cost of painting the outer surface of a closed box, which is 90 cm long. 60cm broad and 45 cm high, at the rate of 75 paise per20sq cm.

Answer 1

Answer:

658.125

Step-by-step explanation:

TSA of Cuboid = 2(lb+bh+hl)

Now , put the digits as given

Then answer comes = 17550 sq cm

17550 ÷ 20 = 877.5

Cost = 877.5 × .75 = 658.125 Answer

Answer 2

Answer: cost of painting = ₹911.25

Step-by-step explanation:

Total surface area of a cuboid =

2 * [ (l*b) + (b*h) + (l*h) ]

Where l = length of the cuboid

b = breadth of the cuboid

h = height of the cuboid

Given,

l = 90 cm; b = 60 cm; h = 45 cm

Using the formula and substituting the values, we get

Total Surface Area = 2 * [ (90*60) + (60*45) + (90*45) ]

=> 2 * [ 5400 + 2700 + 4050 ]

=> 2 * 12150

=> 24300 cm²

Cost of painting per 20 cm² = ₹0.75

Cost of painting 24300 cm² = (24300 * 0.75) / 20 = ₹911

Therefore the cost of painting = ₹911.25

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