Question

25. Lengths of the outer edges of a closed box
are respectively 25 cm, 23 cm and 18 cm.
If thickness of the wood be 2 cm then, find (i) the total internal surface and
090
the cost of painting the internal surface at the rate of 50 paise
Reas​

Answer 1

Answer:

For wooden box

External length=25 cm

External breath=21 cm

And,External height=13 cm

So,external volume=(25×21×13)cm^3=6825cm^3

Thickness=1.5 cm

So,Internal length=25-(1.5×2)=22cm

Internal breadth=21-(1.5×2)=18cm

Internal height=13-(1.5×2)=10cm

So,Internal volume=(22×18×10)cm^3=3960cm^2

1) Now,Volume of wood=External volume-Internal volume

=6825-3960=2865cm^3

2) Rate=Rs.1.50 per cm^3

And,volume=2865cm^3

So,Cost=Rs.(2865×1.50)=Rs.4297.5

3) Volume of cube=(side)^3=(5)^3cm^3=125cm^3

No. of cube=Internal volume/volume of 1 cube

=(3960/125)=31.68cubes

Step-by-step explanation:

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