Question

A tank with rectangular base and rectangular sides, open at the top is to be constructed so that its depth is 2 m and volume is 8 m³. If building of tank costs Rs 70 per sq meters for the base and Rs 45 per square metre for sides. What is the cost of least expensive tank?

Answer 1

Let l, b, and h represent the length, breadth, and height of the tank respectively.
Then, we have height (h) = 2 m
Volume of the tank = 8m³
Volume of the tank = l × b × h

However, the length cannot be negative. Therefore, we have l = 4.

Cost of building the walls = Rs 2h (l + b) × 45 = Rs 90 (2) (2 + 2)
= Rs 8 (90) = Rs 720
Required total cost = Rs (280 + 720) = Rs 1000
Hence, the total cost of the tank will be Rs 1000.