Question 789246
This is exponential decay.  You could treat is like the rate  is a 1% decay each period, here the period being one minute.  During each period, the concentration is 0.99 of what it was in the previous period.


Starting at 10 for 10 grams/gallon, {{{10*(0.99)^n}}} is the concentration of salt present after n number of periods.


You are looking for something about like {{{1>=10(0.99)^n}}} and want to find n.