A cylindrical vessel, without lid, has to be tin-coated on its both sides. If the radius of the base is 70cm and its height is 1.4 m, calculate the cost of tin-coating at the rate of Rs. 3.50 per `1000c m^2dot`

Explanation

Radius of base`=70 cm`
Height`=1.4 m=140 cm`
Lateral surface area`=2pirh`
Area of base`=pir^2`
The total area to be coated`=2(2pirh+pir^2)`
`=2pir(2h+r)`
`=2times22/7times70(280+70)`
`=2times22/7times70times350=44times3500`
`=154000 cm^2`
The cost of coating tin per `1000 cm^2=Rs. 3.5`
Cost for coating tin per `1 cm^2=Rs. 3.5/1000`
Total cost`=`Total area to be coated `times` cost for coating `1 cm^2`
`=154000times3.5/1000=Rs. 539`
`therefore` The cost of tin-coating`=Rs. 539`