Explanation:
Assume that all 93 cartons were 600mL.
Volume of milk = 93 * 0.6L = 55.8L
Difference between Actual and Total
= 79.8L - 55.8L = 24.0L
For every 600mL carton that becomes 1L,
the volume of milk will increase by 0.4L.
=> 24.0L / 0.4L = 60
Hence there were 60 1L cartons and 93 - 60 = 33 600mL cartons of milk.