Answer the questions based on the given information
A school conducted a survey of their school staff to find their beverage preferences. Each of them picked either tea or coffee as their first preference and then with sugar or without sugar as their second preference as shown in the below tree diagram.

Some of the insights from the survey are given below.
♦ 60% percent of the staff prefer coffee.
♦ 90% of those who prefer coffee prefer it with sugar.
♦ 20% of those who prefer tea prefer it without sugar.
(i) What is the probability that a person selected randomly from the staff prefers a beverage with sugar? Show your steps.
(ii) What is the probability that a person from the staff selected at random prefers coffee given that it is without sugar? Show your steps.