In a mixture of milk and water, there is only 26% water

In a mixture of milk and water, there is only 26% water. After replacing the mixture with 7 liters of pure milk, the percentage of milk in the mixture become 76%. The quantity of the mixture is:

AQuA-RAT — Algebra Question Answering with Rationales (Ling et al., DeepMind, 2017) · dev #76