Question

the floor of a rectangle hall has a perimeter 226m. it's height is 4.5m. Find the cost of painting it's four walls at the rate of Rs. 8.40 per square metre

Answer 1

Perimeter of the rectangular floor = 2(l+b)
                                                       = 226 m

Area of 4 walls = 2(l+b)h
                         = 226 × 4.5
                         =1017 m²

Cost of painting the 4 walls = 1017 × 8.40
                                            = Rs. 8542.8

Answer 2

Total cost=rate * Lateral surface area
lateral surface area = 2(l+b)*h
since 2(l+b)=perimeter = 226m,and height =h=4.5m
lateral surface area= 226*4.5
                               =1017sq.m
cost=rate * area
       =8.4*1017
         =Rs.8542.8
Ans therefore it costs Rs.8542.8