Here, the length of wall l = 15 m, the breadth of wall b = 10 m, and the height of wall h = 7 m.
(0.5 mark)
Surface area of the classroom to be painted = lb + 2(bh + hl)
=15×10+2(10×7+7×15)=150+2(70+105)=150+350=500 m2
(2 marks)
Now, the required number of cans=Area of hallArea of one can=500100=5 cans
Hence, 5 cans are required to paint the room.
(0.5 mark)