A scientist begins an experiment with 20.25 milliliters of a chemical. She adds 0.75 milliliter of water to the chemical every 10 minutes, starting at 1:30 P. M. B. The scientist continues to add 0.75 milliliters every 10 minutes, rounded to the nearest whole number, what percent of the mixture of the chemical and water is made up of water at 3:40 P. M.?

Show or explain all your work.