The cost of painting the inner curved surface area of a cylindrical container of depth 20 m is ₹ 8800. If the painter charges ₹ 40 per metre square to paint the cylindrical container, then find its radius.
[ Take π=227 ]
1.75 m
Cost of painting the inner curved surface
= ₹ 8800
Cost of painting per square metre
= ₹ 40
Hence, area that was painted
= 880040=220 m2
Thus, inner curved surface area
=220 m2
Inner curved surface area of cylinder
=2πrh
Height of cylinder = 20 m.
⇒2×227×r×20=220
⇒r=220×720×2×22
⇒r=1.75 m
Hence, radius of the cylinder = 1.75 m.