Question

Find the cost of digging a cuboidal pit 8m long, 9m broad and 3m deep at rate of rupees 40per meter square

Answer 1

l=8 m, b=6 m, h=3 m

Volume =l×b×h=(8×6×2)m3=144m3

Cost of digging per m3 volume =Rs.30

Cost of digging per 144m3 volume =Rs.144×30

= Rs. 4320

Answer 2

Given cuboid dimensions

Length = 8m

Breadth = 9m

Height = 3m

Rate per m² = Rs40

Total cost = Total surface area × 40

⇒2(lb + bh + hl) ×40

⇒2[(8×9) + (9×3) + (3×8)] ×40

⇒2(72+27+ 24) ×40

⇒2(121)×40

⇒242×40

∴Rs 9680 is the total cost to dig the pit.