Given, diameter of the glass = 7 cm
Radius of the glass,
r=72 cm
∴ Milk contained in the cylindrical glass = Volume of the cylindrical glass
=πr2h=227×72×72×12=462 cm3
Now, milk required for 1600 students
= milk required by one student× number of students
=462×1600=739200 cm3
=7392001000=739.2 L [∵1 cm3=11000 L]
Hence, 739.2 L milk is needed to serve 1600 students.