A website Maths Puzzle Numerical Ability Alligation or Mixture

In a 140L of a mixture of milk and water percentage of water is only 30%. This milkman gave 20L of this mixture to a customer. Then, the added equal quantities of pure milk and water to the remaining mixture. As a result, the respective ratio of milk and water in the mixture become 2: 1. What was the quantity of milk added?
(a) 12L
(b) 16L
(c) 18L
(d) 8L

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Q5. When one litre of water is added to a mixture of acid and water, the new mixture contains 20% acid. When one litre of acid is added to the new mixture, then the resulting mixture contains 100/3% acid. The percentage of acid in the original mixture was

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There are 1000 wine bottles. One of the bottles contains poisoned wine. A rat dies after one hour of drinking the poisoned wine. How many minimum rats are needed to figure out which bottle contains poison in hour.