1. 
Grace is concentrating a sample by distillation. She started with 110 ml of a solution that was about 0.04% inorganic salts. After several hours of distillation the amount of inorganics salts hasn't changed, but the volume had been decreased to 50 ml. What percent of the solution after distillation is inorganic salts? Round your answer to the nearest hundredth of a percent.


2. 
Courtney performed an analysis on some water from Bigtown Lake. She tested four samples and found the lead concentrations to be in parts per million (micrograms per milliliter or mg per liter) to be 1.035, 1.028, 1.015, and 1.026 respectively. What was the average mass of lead? Round your answer to the nearest thousandth.

