Answer:
₹9600
Explanation:
The surface area of the tank is ...
S = 2(LW +H(L+W)) = 2(12·9 +4(12+9)) = 2(108 +84) = 384 . . . . square meters
If the sheet is 2 m wide, it will take a length of ...
384 m²/(2 m) = 192 m
At a cost of ₹50 per meter, the cost will be ...
(₹50/m)·(192 m) = ₹9600
The iron sheet required will cost 9600 rupees.