I don't really get this question at all

N

Needhelp4math

New member
Joined
Jan 10, 2019
Messages
21
"The Diagram Shows a cylinderal water tank of diameter 4.2m and height of 2.5m. The curved surface and the top of the tank need to be painted. If one liter of paint covers 8m^2 and paint sold is in 2 liter cans, how many cans of paint are needed to paint the tank?"

What does this question mean by "curved surface and the top of the tank need to be painted" isn't the surface on top?

And what does it mean by covering 8m^2 and being sold in 2 liter cans.

Covering what?

And please don't ask for my work, i don't even know how to start this question.

Thanks.


10da1c4ba214995bb57022c49525517e.jpg
 
Last edited:
Needhelp4math said:
"The Diagram Shows a cylinderal water tank of diameter 4.2m and height of 2.5m. The curved surface and the top of the tank need to be painted. If one liter of paint covers 8m^2 and paint sold is in 2 liter cans, how many cans of paint are needed to paint the tank?"

What does this question mean by "curved surface and the top of the tank need to be painted" isn't the surface on top?

And what does it mean by covering 8m^2 and being sold in 2 liter cans.

Covering what?

And please don't ask for my work, i don't even know how to start this question.

Thanks.

Sent from my LG-H831 using Tapatalk
Click to expand...

I won't ask for your work, but I must demand at least the drawing. I do not believe you do not know where to start. Lateral surface area of a right, circular cylinder? Area of a circle? What is the surface area to be painted - in units of m^2? Of course, I'm just guessing since I have no idea what your water tank looks like.
 
Needhelp4math said:
"The Diagram Shows a cylinderal water tank of diameter 4.2m and height of 2.5m. The curved surface and the top of the tank need to be painted. If one liter of paint covers 8m^2 and paint sold is in 2 liter cans, how many cans of paint are needed to paint the tank?"

What does this question mean by "curved surface and the top of the tank need to be painted" isn't the surface on top?

And what does it mean by covering 8m^2 and being sold in 2 liter cans.

Covering what?
Click to expand...

I think you're primarily asking about the meaning of various words. Let's look at each of them.

The diagram shows a cylindrical water tank of diameter 4.2m and height of 2.5m.
The curved surface and the top of the tank need to be painted.
If one liter of paint covers 8m^2 and paint is sold in 2 liter cans, how many cans of paint are needed to paint the tank?
​

The top of the tank is a (flat) circle (disk). This is not what we mean by "curved surface".

The curved surface is what should have been called the lateral surface, but they probably wanted to avoid big words. It is the surface around the sides, which is curved (not flat).

You should have learned a formula for the lateral area of a cylinder, and another for the area of a circle.

If you buy a can of paint, it will often tell you how much area it can cover, that is, what area can be painted using one can. In this case, you are instead told how much area each liter can cover: you will need one liter of paint to cover each 8 square meters. From that you can find how many square meters one can (2 liters) can cover. And then you can find how many cans you need by dividing the total area by that.

Now give it a try. What are the formulas you need? What areas do they give you?
 
I got a surface area of 46.84(which is right) by adding the Area of a circle and lateral surface together.
But i seem to still be stuck on the 2nd part of the question, where you need to find the amount of cans needed to paint the tank.

Apparently you need 3 cans

Im getting 2.9275, is that right?
(46.84/16)
 
Last edited:
Needhelp4math said:
I got a surface area of 46.84(which is right) by adding the Area of a circle and lateral surface together.
But i seem to still be stuck on the 2nd part of the question, where you need to find the amount of cans needed to paint the tank.

Apparently you need 3 cans

Im getting 2.9275, is that right?
Click to expand...
Ah you have some work to show us, so please show it. Please understand that it is not fair for you to want me to calculate how many cans of paint is needed just to see if you are correct. You should show us your work. That way if you made a mistake we can point out that mistake and if you got it right then we can tell you good job. Thank you.
 
Jomo said:
Ah you have some work to show us, so please show it. Please understand that it is not fair for you to want me to calculate how many cans of paint is needed just to see if you are correct. You should show us your work. That way if you made a mistake we can point out that mistake and if you got it right then we can tell you good job. Thank you.
Click to expand...
Hey jomo can you please stop acting like a bot

Sent from my LG-H831 using Tapatalk
 
Needhelp4math said:
Hey jomo can you please stop acting like a bot

Sent from my LG-H831 using Tapatalk
Click to expand...
Jomo said:
Ah you have some work to show us, so please show it. Please understand that it is not fair for you to want me to calculate how many cans of paint is needed just to see if you are correct. You should show us your work. That way if you made a mistake we can point out that mistake and if you got it right then we can tell you good job. Thank you.
Click to expand...
And also i did

Sent from my LG-H831 using Tapatalk
 
Needhelp4math said:
I got a surface area of 46.84(which is right) by adding the Area of a circle and lateral surface together.
But i seem to still be stuck on the 2nd part of the question, where you need to find the amount of cans needed to paint the tank.

Apparently you need 3 cans

Im getting 2.9275, is that right?
Click to expand...
Assuming that 2.9275 cans is exactly what you need (and it is!) do you understand why you have to buy 3 cans?
 
You must log in or register to reply here.
Top