Answer:
Single discount rates are one off discounts which are given by seller on certain products with certain conditions which most be met for it to apply such conditions can be for buyers who pay in cash, buyers who buy in bulks e.g buy 10 get one free, or for every 5 bought you get a 5% discount e.t.c.
This is related to chain discount because its also a series of discount which is allowed for list price of products or services.