Answer:
2
Explanation:
To find the solution we must first make the transformations to international units,
In this way:
![260cy / hr * 27ft ^ 3 / cy = 7020 ft ^ 3 / hr](https://tex.z-dn.net/?f=260cy%20%2F%20hr%20%2A%2027ft%20%5E%203%20%2F%20cy%20%3D%207020%20ft%20%5E%203%20%2F%20hr)
Inches of length (L) to feet =
![7in * ft / 12in = 0.588ft](https://tex.z-dn.net/?f=7in%20%2A%20ft%20%2F%2012in%20%3D%200.588ft)
So we can identify the area by hour:
![A / h = 7020 / 0.588 = 12034.28 ft ^ 3 / hr](https://tex.z-dn.net/?f=A%20%2F%20h%20%3D%207020%20%2F%200.588%20%3D%2012034.28%20ft%20%5E%203%20%2F%20hr)
Once the area is identified, we now identify the number of passes required,
Passes required = Area x number of passes
![P_{r} = 12034.28 * 4](https://tex.z-dn.net/?f=P_%7Br%7D%20%3D%2012034.28%20%2A%204)
![P_{r} = 48136ft ^ 2 / hr](https://tex.z-dn.net/?f=P_%7Br%7D%20%3D%2048136ft%20%5E%202%20%2F%20hr)
We transform speed to international units
![V = 2mph * 5280ft / mi](https://tex.z-dn.net/?f=V%20%3D%202mph%20%2A%205280ft%20%2F%20mi)
![V = 10560ft / hr](https://tex.z-dn.net/?f=V%20%3D%2010560ft%20%2F%20hr)
So we can identify the covered area
![covered_ {area} = v * m * p](https://tex.z-dn.net/?f=covered_%20%7Barea%7D%20%3D%20v%20%2A%20m%20%2A%20p)
where
<em>m = drum widht</em>
<em>p = efficiency</em>
![covered_{area} = 10560 * 4.16 * (55/60) = 40269ft ^ 2](https://tex.z-dn.net/?f=covered_%7Barea%7D%20%3D%2010560%20%2A%204.16%20%2A%20%2855%2F60%29%20%3D%2040269ft%20%5E%202)
In this way we obtain the number of rollers given by:
No. of Rollers = Passes required / covered area
No of rollers = 48136/40269
No of rollers = 1.19, that is, 2.
Number of rollers required are 2.