Question

An open rectangular tank has dimension 200cm x200cm x 40cm.Find the cost of polishing its inner surface area at rate of Rs.200 per metre square.

Answer 1

surface area = 2LB +2 BH + 2LH
                     =2(4 + 0.8 +0.8)
                      = 11.2 m²
now, cost = 200 ×11.2
                = Rs 2240

Answer 2

Answer:

Rupees 1440

Step-by-step explanation:

Area of tank= Total surface area- area of ceiling

= 2(lb+lh+ bh) -lb

2(200 cm× 200cm+200cm × 40 cm+200cm × 40 cm) -200 cm×200 cm

convert cm to m

= 2( 2×2+2×0.4+2×0.4) - 2×2

2(4+0.8+0.8) -4

2(5.6) - 4

11.2-4

= 7.2 m²

Cost of polishing- 7.2 × 200= Rupees 1440