A 100 gallon tank contains 25 pounds of dissolved salt. Pure water enters at a rate of 8 gallons per minute. The mixture is kept thoroughly mixed and drains at a rate of 7 gallons per minute. Let y = y(t) = salt amount(lbs) at time t(minutes). Then y' =rate in rate out. (a) Which differential equation models the change in salt content at time t? O y = 7y': = y(0) = 25 100 O y' = (0)= O y' = 1- y(0) = 25 O y'= y(0) = 25 100 O 7y y(0) = 25 100+ t Part 2 of 2 Ty The correct differential equation is y EINE y(0) 25 100 t (b) Solve the differential equation to determine the salt amount in terms of time. y(t) (c) Determine the salt amount after 19 minutes. y(19) pounds b By 100+ t 8y 100+ t Ty <<= 25
