Question

a plastic box 1.5m long 1.25 m wide and ,65cm deep is to be made

Answer 1

so what we have to do

Answer 2

$\sf\underline{Question:}$

A plastic box 1.5 m long, 1.25 m wide and 65 cm deep is to bs made. It is to be open at the top. Ignoring the thickness of the plastic sheet, determine ,

• The area of the sheet required for making the box.

• The cost of sheet for it, if a sheet measuring 1 m ² costs Rs. 20

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$\sf\underline{Answer:}$

(i) We have,

$\sf{l=length\:of\:plastic\:box=1.5m}$

$\sf{b=breadth\:of\:plastic\:box=1.25}$

$\sf{h=height\:of\:plastic\:box=65cm=0.65m}$

$\rightarrow$ $\sf{Total\:surface\:area\:of\:plastic\:box=lb+2(bh+hl)}$

$\leadsto$ $\sf{[1.5×1.25+2(1.25×0.65+0.65×1.5)]m^2}$

$\leadsto$ $\sf{[1.875+2×(0.8125+0.975)]m^2}$

$\leadsto$ $\sf{(1.875+3.575)m^2}$

$\sf\underline{5.45\:m^2}$

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• Since 1 m² sheet costs Rs.20 . Therefore,

Cost of sheet required for making the box = Area of the sheet × rate per sq. metre

$\Rightarrow$ Rs. (5.45 × 20)

= Rs. 109