A school water tank drains such that the volume of water remaining after t minutes is given by the linear polynomial V(t)=12.5−0.25t (in kilolitres).
a. (i) For what value of t will the tank become empty?
b. (ii) How many minutes after the start of drainage will exactly 3 kilolitres of water remain in the tank?
c. (iii) Interpret the physical meaning of the zero obtained in part (i) with respect to the situation.