A tank with length, breadth and height of 8, 6 and 4 units respectively is open at the top. Find the cost of painting inside the tank at the rate of ₹10 per sq.units.
Area inside the tank = Lateral Surface Area + floor area
=2h(l+b)+lb
=2×4(8+6)+8×6
=160 sq.units
Cost of painting 1 sq. unit = ₹10
So, total cost of painting
=₹10×Area inside the tank
=10×160
=₹1600