Milk–water mixture parts 11:2:\nAfter adding 35 L water, the mixture contains twice as much milk as water. Find original pure milk (L).

Introduction / Context:
Given a parts ratio and an addition of water, enforce the final condition milk = 2*water to find original quantities.

Given Data / Assumptions:

• Original milk:water = 11:2 ⇒ milk = 11k, water = 2k.
• Add 35 L water ⇒ final water = 2k + 35.
• Final condition: milk = 2*(final water).

Concept / Approach:
11k = 2*(2k + 35) ⇒ solve k, then compute milk = 11k.

Step-by-Step Solution:

Verification / Alternative check:
Original water 20 L; after addition 55 L; milk 110 L is indeed twice water 55 L.

Why Other Options Are Wrong:
55 is water after addition; 70, 220 mismatch the given condition.

Common Pitfalls:
Doubling the original water rather than the final water (which includes the added 35 L).

Final Answer:
110