Question

A room is 8.5 m long 6.5 m broad and 3.4 m high.It has two doors each measuring (1.5 m by 1 m) and two windows each measuring (2 m by 1 m).Find the cost of painting it four walls at rs160 per m²

Answer 1

area of four walls= 2[(l+b)×h]
= 2[(8.5 + 6.5) ×3.4]
=2[15×3.4]
=2×51
= 102m^2

Area of two doors =2[l×b]
=2[1.5×1]
=2×1.5
= 3m^2

area of window = 2[l×b]
=2[2×1]
=2×2
=4m^2

area of four walls excluding the doors and windows= area of four walls _ area of door + area of window
=102 _ 3+4
= 102 _ 7
=95m^2

cost of painting its four walls = area of four walls excluding doors and windows ×160 per m^2
=95×160
=15200rupees

Answer 2

the area of four walls=2h(l+b)=2*3.4(6.5+8.5)=102m2
area of walls without door and windows=102-area of door-2*area of windows
                                                               =102-1.5-2*2=96.5
the cost of paint=96.5*160=15440rs