Question

the internal measure of a cuboidal room are 18m×16m×8m find the total cost of whitewashing if the cost of whitewashing is 7rs per meter.what will be it's cost if ceiling is also whitewashed​

Answer 1

Answer:

TSA of cuboid =

$2(lb + lh + bh)$

$= 2(18 \times 16 + 16 \times 8 + 18 \times 8)$

$= 2(288 + 128 + 144)$

$= 2 \times 560 = 1120$

so, floor will not be white washed ,

$tsa \: - l \times b$

$= 1120 - 288 = 832$

so cost of white washing is,

$= 832 \times 7 = rs. 5824$

$mark \: brainliest$

Answer 2

Question

The internal measure of a cuboidal room are 18m×16m×8m find the total cost of whitewashing if the cost of whitewashing is 7rs per meter. What will be it's cost if ceiling is also whitewashed.

Answer

Total cost of whitewashing all four walls and ceilings is Rs. 5824

Given

• Length = 18m
• Breadth = 16m
• Height = 8m

To Calculate

Area of whitewashing =

L.S.A. of room + Area of ceiling

Solution

l = 18m

b = 16m

h = 8m

$\bf↦ L.S.A \: of \: room =2h(l + b)$

$\bf↦2 \times 8(18 + 16)$

$\bf↦2 \times 8 \times 34$

$\bf↦2 \times 272$

$\bf↦544 {m}^{2}$

Area of ceiling =

$\bf↦length \times breadth$

$\bf↦18 \times 16$

$\bf↦288 {m}^{2}$

Total Area = Area of walls + Ceiling

$\: \: \: \: \bf↦544 {m}^{2} + 288 {m}^{2}$

$\: \: \: \: \bf↦832 {m}^{2}$

Total Cost of whitewashing =

$\bf↦rate \times total \: area$

$\bf↦832 \times 7$

$\bf↦ rs.5824$

Therefore, Cost of whitewashing is Rs. 5824