Each 1 L of fruit punch uses 300 ml concentrate, so water = 1000 − 300 = 700 ml.<br><br>
&bull; For 15 L of fruit punch: water = 15 × 700 = 10 500 ml<br>
&bull; 10 500 ml = 10 L 500 ml<br><br>
Final Answer: 10 L 500 ml