Question

A water tank is 30 m long, 20 m wide and 12 m deep. It is made up of iron sheet which is 3 m wide. The tank is open at the top. If the cost of the iron sheet is Rs 10 per metre, then the total cost of the iron sheet required to build the tank is 

(a) Rs 6000 

(b) Rs 8000 

(c) Rs 9000 

(d) Rs 10000

Answer 1

(a) 

Surface area of the open tank 

= [2 x (20 x 12 + 30 x 12) + 30 x 20] m² 

= [2 x (240 + 360) + 600]  m² 

= 1800 m² 

∴ Length of the iron sheet = \(\frac{1800}{3}\) = 600 m 

Cost of the iron sheet = Rs (600 × 10) = Rs 6000.