About This Set
These questions are a step up, closer to Tier 2: most need two steps or a careful setup, such as a chain of pours between two vessels, a replacement made with another mixture instead of water, or a mixing ratio hidden behind a selling price and a loss. If you are preparing for Tier 1 only, the [Tier 2] items can wait. Allow about 35 minutes and do the full set before reading any explanation. 18 or more right means you can handle the harder mixture questions. With fewer, read the explanations of the ones you missed and try those again a few days later.