The Total solution for NCERT class 6-12
Surfacearea of a cuboidal hall without bottom = Total surface area – Area of base= 2 [lb + bh + hl] – lb= 2 [15 × 10 + 10 × 7 + 7 × 15] – 15 × 10= 2[150 + 70 + 105] – 150= 2 [325] – 150= 650 – 150= 500 m2Area of the paint in one can = 100 m2Number of cans required = 500 =5 cans.