Question

A rectangular room is 4.5 m long,4 m wide and 3 m high. Find the cost of white washing [3]
its walls and the roof at ₹ 7.50 per square metre.

Answer 1

Step-by-step explanation:

Area of wall =lxbxh

= (4.5 x 4 x 3)m

=54m square

now,the cost of whitewashing the wall = 54m × ₹7.50 = ₹405

Answer 2

$total \:cost \: of \: white \: washing \: in \: walls \: \\ = \: 3 \times 4.5 + 3 \times 4 \\ \\ = 13.5 + 12 \\ = 25.5 \times 2sides \\ = 51 {m}^{2} \\ \: cost \: of \: white \: washing \: in \: walls \: \\ = \: 51 {m}^{2} \times 7.50 \\ = \: rs \: 382.5 \\ \\ area \: of \: roof \: = \: 4 \times 4.5 \: \\ = 18.0 \\ = cost \: of \: white \: washing \: \\ = \: 18 \times 7.50 \\ = \: \: rs 135$