A bottling plant uses a syrup concentrate to make a fruit drink. Originally, 500 mL of concentrate was used to produce 4000 mL of drink. A new, more efficient mixing process allows the same 500 mL of concentrate to produce 5000 mL of drink. If the plant needs to produce 3000 mL of the fruit drink using the new efficient mixing process, how many milliliters of the concentrate should they use?