Question

a room is 7 m . long 7m. wide and 3.5 m hight find the cost of covering its walls with a wall paper at the rate of rs. 3 per meter square

Answer 1

Length of room = 7m
Width of room   = 7m
Height of room  = 3.5m
We know that there are 5 walls (4 walls + 1 ceiling) in room
  So, area of 5 walls = 2(l+b)h + l × b
                                = 2(7+7)3.5 + 7×7
                                = 28×3.5 +49 = 98+49 = 147m²
Cost of covering 1m² of wall  with wall paper = Rs 3
∴ Cost of covering 147m² of wall  with wall paper = Rs 147× 3 = Rs 441
                                    Thank You!!!!!Hope this helps!!!!