Find t(4)(n) for the function t(n)=3n-1/3 +2n5/3

A large tank contains 140 litres of water in which 20 grams of salt is dissolved. Brine containing 15 grams of salt per litre is pumped into the tank at a rate of 6 litres per minute. The well mixed solution is pumped out of the tank at a rate of 3 litres per minute. (a) Find an expression for the amount of water in the tank after t minutes. (b) Let x(t) be the amount of salt in the tank after t minutes. Which of the following is a differential equation for x(t)? (A) (E) (I) dt 90 || 3 x(t) 140 + 3t 6 (B) d 6 x(t) 140 + 3t 3 x(t) 140 + 6t dt dx dx 3 = 90 − x(1) (F) = 18 - 1*(7) (G) = 18 - dt dt 140 x(t) (C) dx dt = 18 3 x(t) 140 + 6t 6 x(t) 140 + 6t (D) (H) dx = 90 3 140 x(t) 6 x(t) 140 + 3t

A ship is moving at a speed of 30 km/h parallel to a straight shoreline. The ship is 4 km from shore and it passes a lighthouse at noon. (a) Express the distance s between the lighthouse and the ship as a function of d, the distance the ship has traveled since noon. S = f(d) = (b) Express d as a function of t, the time elapsed since noon. d = g(t) = √² + 16 X (c) Find fo g. (fog)(t) =

f(6) if f(x) = 2x – 5