Milk left $= 40 imes [1 - (4/40)]^3 = 40 imes (9/10)^3 = 40 imes (729/1000) = 29.16$ litres.
शेष दूध $= 40 imes [1 - (4/40)]^3 = 40 imes (9/10)^3 = 40 imes (729/1000) = 29.16$ लीटर।