A big iron boiler tank which is open on the top is cylindrical in shape. Its height is 10 m and radius is 7 m. It gets corroded at a rate of 3 sq. meter/day. The number of days in which it totally gets corroded is (Take pi=227)
198
Surface area of the boiler = Curved Surface area + Bottom area
=2πrh+πr2
=2×227×7×10+227×72
= 594 sq. meter
Total number of days =Total Surface Area of tankArea corroded per day=5943=198