initially tank i contains 100 litres of salt brine with a concentration of 1 kilogram per litre, and tank ii contains 100 litres of water. liquid is pumped from tank i into tank ii at a rate of 1 litre per minute, and liquid is pumped from tank ii into tank i at a rate of 2 litres per minute. the tanks are kept well stirred. let a1 be the amount of salt in kilograms in tank i and a2 be the amount of salt in pounds in tank ii.
(a) calculate a1(t) and c1(t). for which range of values of t are the expression for a1(t) and c1(t) valid?
(b) what is the concentration in tank i after 10 minutes?