Question

Find the cost of painting the four walls and ceiling of a room of dimensions 5m*4m*3m at the cost of rs 10 per m^

Answer 1

2(l+b)h=2(5+4)3=54+area of celling
=54+5×4=74m
$74 {m}^{2}$
now cost of
${1m}^{2} = 10rs$
so 74 ×10=740rs

Answer 2

Given :

Length of room = 5 m

Breadth of room = 4 m

Height of room = 3 m

To Find :

Find the cost of painting the four walls and ceiling of a room

Solution:

Length of room = 5 m

Breadth of room = 4 m

Height of room = 3 m

Area of 4 walls+area of ceiling = 2(l+b)h+lb

Area of 4 walls+area of ceiling = $2(5+4)(3)+(5 \times 4)$

Area of 4 walls+area of ceiling = 74 sq.m.

Cost of painting 1 sq.m. = Rs.10

Cost of painting 74 sq.m. = $74 \times 10 = Rs.740$

Hence The cost of painting the four walls and ceiling of a room is Rs.740