A school provides milk to the students daily in a cylinder glass of diameter `7` `cm`. If the glass is filled with milk up to an height of `12` `cm`, find how many litres of milk is needed to serve `1600` students.

Explanation

Given, diameter of glass = 7 cm
Radius of glass, `r = (7)/(2) cm`
`therefore` Milk contained in the cyllindrical glass = volume of cylindrical glass
` pir^(2)h = (22)/(7) xx (7)/(2) xx (7)/(2) xx 12 = 462 cm^(3)`
Now, milk required for 1600 students `= 462 xx 1600 = 739200 cm^(3) `
`" "(739200)/(1000) = 7392 L" "[because 1 cm^(3) =(1)/(1000)L]`
Hence, 739.2 L milk is needed to serve 1600 students.