A solution contains liquids A and B in the ratio 4:7. If 14 liters of the mixture is drawn off and replaced with liquid B, the ratio becomes 2:5. What was the original volume of the mixture?
Correct: B
Let the original volume be V liters. The removal and replacement process follows the formula: Final ratio = (Initial ratio * (1 - 14/V)^1) + (Replacement component * (14/V)). For liquid A, initial ratio 4/11 becomes (4/11)(1 - 14/V), and final ratio 2/7. Solve (4/11)(1 - 14/V) = 2/7 => (1 - 14/V) = 11/14 * 2/4 = 11/28. Thus, 14/V = 17/28 => V = 14*28/17 ≈ 56 liters.