Container A had 7 units and Container B had 10 units. After pouring 300 ml from A to B, A has 4 units and B has 13 units. The total of 17 units never changes. A lost 3 units = 300 ml.<br><br>[[model:questions/solutions/q4379.png]]<br><br>• At first → A = 7u, B = 10u, total = 17u<br>• After transfer → A = 4u, B = 13u, total = 17u (unchanged)<br>• A lost → 7u − 4u = 3u = 300 ml<br>• 1 unit → 300 ÷ 3 = 100 ml<br>• Total → 17u = 17 × 100 = 1700 ml<br><br>There were 1700 ml of water altogether.<br>Check: A = 700 ml, B = 1000 ml. 700:1000 = 7:10. After: A = 400 ml, B = 1300 ml. 400:1300 = 4:13. ✓