An open cubical tank (without a lid) has an edge of 1.5 m. What is the cost of painting its outer surface, excluding the base it stands on and the open top, at Rs. 40 per square metre?
Correct answer B. Rs. 360
Explanation
Only the four side faces are painted. Area = 4 x 1.5 x 1.5 = 9 sq m. Cost = 9 x 40 = Rs. 360.
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