Question

A room is 8.5 m long,6.5 m broad and 3.4 m high. It has two doors, each measuring (2 m 1m).Find the cost of painting its four walls at £160 per m.

Answer 1

$l=8.5m\\w=6.5m\\h=3.4m\\------------------\\Area\ of\ 4\ walls:A_w=2lh+2wh\\\\A_w=2\times8.5\times3.4+2\times6.5\times3.4=57.8+44.2=102\ (m^2)\\------------------------------\\Area\ of\ the\ 2\ doors:A_d=2\times2\times1=4\ (m^2)\\-----------------------------\\The\ area\ to\ be\ painted:A=A_w-A_d\\\\A=102m^2-4m^2=98m^2\\---------------------------\\The\ cost\ of\ painting:98\times\£160=\boxed{\£15,680}\leftarrow Answer$