Answer
Let t be number of minutes since tap is opened
water is increased by 20 gallons of water per minute.
sugar increase rate of 3 pounds per minute
water :- W(t) = 350 + 10 t
sugar :- S(t) = 10 + 3 t
concentration
C(t) =
at t = 15 minutes
C(15) =
C(15) =
C(15) = 0.11
at beginning t = 0 minutes
C(0) =
C(0) =
C(0) = 0.0286
C(15) > C(0)
hence, concentration is increasing as time is passing.