The length, breadth and height of a room are 5 m, 4 m and 3 m respecti

1.	The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs. 7.50 perm2.
Answer» Length of room, l = 5 m breadth, b = 4m height, h = 3 m White washing the room and the ceiling except floor to be made. ∴ Area, A = lb + 2bh + 21h = lb + 2h(b + l) = (5 × 4) + 2 × 3(4 + 5) = 20 + 6(9) = 20 + 54 = 74 m² . Cost of white washing for 1 sq.m. is Rs. 7.50 ∴ Cost of white washing 74 sq. m. is ? = 74 × 7.50 = Rs. 555.

The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs. 7.50 perm2.

Answer»

Length of room, l = 5 m

breadth, b = 4m

height, h = 3 m

White washing the room and the ceiling except floor to be made.

∴ Area, A = lb + 2bh + 21h

= lb + 2h(b + l) = (5 × 4) + 2 × 3(4 + 5)

= 20 + 6(9)

= 20 + 54 = 74 m² .

Cost of white washing for 1 sq.m. is Rs. 7.50

∴ Cost of white washing 74 sq. m. is ?

= 74 × 7.50

= Rs. 555.