Question

Hameed has built a cubical water tank with the lid of his house with each outer edge 1.5 metre long its outer surface area of the tank excluding the best covered with square tiles of side 25 cm how much he would spend for tiles if the cost of the tiles is 360 per dozen.

Answer 1

surface area of tank = 5(1.5*1.5) = 11.25 sq m
area of tiles = .25*.25 =0.0625 sq m
no. of tiles required = 11.25/0.0625 = 180 = 15 dozen
cost of 1 dozen = 360
cost if 15 dozen = 15*360 = rs. 5400

Answer 2

Here you go--

Area of the cubical tank=$5a^2$

Given that a=1.5 m or 150 cm

Therefore, Area of cubical tank =5*150*150

=112500 $cm^2$

Area of Square tile=$s^2$

Given that, s=25 cm

=25*25=625 $cm^2$

Number of tiles required= Area of cubical tank/Area of 1 tile

=112500/625=180 tiles

Now,Cost of 12 tiles= Rs. 360 (Given)

Cost of 1 tile=360/12=Rs.30

Cost of 180 tiles= 30*180=Rs. 5400

Hence the total cost is Rs. 5400

Hope this helps you..

Concept :

If I explain in short then you must find the surface area of tank and tile and then divide it to know number of tiles required and then multiply it by the cost of 1 tile to find total cost

Don't forget :

To convert m to cm by multiplying by 100

Some important Formulae to know :

See the picture attached for formulas of this chapter

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