A carpenter cuts wooden planks whose lengths form an arithmetic progression. The first plank is 95 cm long and each subsequent plank is 5 cm shorter than the one before it.
(i) Set up an inequality involving n that represents the condition that the total length of the first n planks is at least 500 cm.
(ii) Solve the inequality to find the greatest possible value of n.
(iii) Find the exact total length of wood used for that value of n.