Measurement of big box, l = 25 cm.
b = 20 cm.
h = 5 cm.
∴ TSA of eacxh big box = 2(lb + bh + lh)
= 2 [25 × 20 + 20 × 5 + 25 × 5]
= 2 [500 + 100 + 120]
= 2 (725) T.S.A. =1450 cm2 .
For all the overlaps 5% of the total surface area is required extra.
\(\frac{5}{100} \times1450\)
= 72.5 cm2 .
∴ Total surface area of big box,
TSA = 1450 + 72.5 = 1522.5 cm2 .
Area required for 1 box is 1522.5 cm2
Area required for 25 boxes … ?…
= 1522.5 × 250 = 380625 cm2 .
Dimension of small box, l = 15 cm. b = 12 cm. h = 5 cm.
∴ TSA of each small box = 2(lb + bh + lh)
= 2 [15 × 12 + 12 × 5 + 15 × 5]
= 2 [180 + 60 + 75] = 2 × 315
= 630 cm2 .
More area to overlap cardboard is 5% more.
For 100 cm2 , 5 cm2
For 630 cm2 , …?… = 31.5 cm2 .
∴ T.S.A.= 630 + 31.5= 661.5 cm2 .
TSA required for 1 box is 661.5 cm2
TSA required for 250 boxes …?… = 661.5 × 250 = 165375 cm2 .
∴ To prepare 500 boxes, TSA = 380625 + 165375 = 546000 cm2 .
Cost of 1000 sq.cm, of cardboard is Rs.4 Cost of 546000 sq.cm of cardboard is ?
= Rs. 2184