Question

It is required to make a plastering of sand and cement with 3.5 cm thick surrounding four cylindrical pillars each of whose diameter is 17.5 cm
(i) If each pillar is of 3 metre height let us write by calculating how many cubic dcm of plastering will be needed.
(ii) If the ratio of sand and cement in the plaster material be 4:1 let us write how many cubic dcm of cement will be needed.​

Answer 1

Answer:

1 quintal = 100kg.

9.24 quintals = 924 kg.

1.5 kg = 1 dm³

924 kg = 6.16 dm³

volume of wood = surface area × height

6.16 = 440 × h

h = 6.16/440 = 0.014 dcm

surface area = πr² = 440

r = √440/3.14 = 11.84 dcm

surface area of piler = 2πrh = 2 × 3.14 × 17.5/2 × 300 = 16485 cm²

volume of plaster = surface area of piller × thickness of plaster

= 16485 × 3.5 = 57697.5 cm²

volume of plaster for 4 pillers = 4 × 57697.5 = 230790 cm³

= 230.79 dcm³

sand = 230.79 × 4/5 = 184.63 dcm³

cement = 230.79 – 184.63 = 46.16 dcm³