Question

a closed box is cuboid in shape with length 40cm,breadth 30 cm height 50 cm.It is made up of thin metal sheet.Find the cost of metal sheet required to make 20 such boxes,if 1 metre square of metal sheet costs rupees 45

Answer 1

Length of box= 40cm
breadth of box= 30cm
and,
height of box = 50cm
Metal is required for making the cuboidal box= TSA of box= 2(lb+bh+hl)
= 2(40×30+30×50+50×40)= 2(1200+1500+2000)= 2×4700= 9400cm²

9400cm²= 9400/100=94m²
Cost of metal of per m²=45
Therefore,
Cost of metal of 94m²= 94× 45= Rs 4230

HOPE IT IS CLEAR..
PLZZZ MARK IT AS BRAINLEIST.

Answer 2

Given:- (eq. means equation)
L = 40cm
B = 30cm
H = 50cm
As we know,
Total surface area of cuboid=2(l×b+b×h+h×l)
=2 (40×30 + 30×50 + 50×40)
=2 (1200 + 1500 + 2000)
=2 (4700)
=2 × 4700 [when we remove bracket then we add multiply sign (×)]
=9400cm²
so, area of sheet needed to make 1 box of length 40cm, breadth 30cm and height 50cm is 9400cm². -eq.1

As we know,
cost of 1m² sheet = ₹45
(Now, we need to make the units same of our total surface area of cuboidal box and sheet we can get in ₹45)
so,
As 100cm = 1m,
then,
cost of 100cm²sheet = ₹45 {because 100cm = 1m(now we have both the units same)}

cost of 100cm² sheet = ₹45
cost of 1cm² sheet = ₹45/100 eq-2

cost of 9400cm² sheet= cost of 1cm² sheet × 9400cm²
= 45/100×9400
= ₹4230
now, we got that the cost of making 1 box is ₹4230
so to know the price of 20 such boxes we multiply both.

cost of 20 boxes=20×4230
= ₹ 84,600