A 9th class has 15 boys and 30 girls. Two representatives are to be selected at random from the class. Find the probability that, (i) the first representative is a girl.
(ii) the second representative is a girl, given that the first representative is a boy.
(iii) first is a boy and second is a girl.
(iv) a girl and a boy is selected as representatives.

The business cycle is the periodic but irregular up-and-down movement in economic activity, measured by fluctuations in real gross domestic product (gdp) and other macroeconomic variables. a business cycle is typically characterized by four phases—recession, recovery, growth, and decline—that repeat themselves over time. economists note, however, that complete business cycles vary in length. the duration of business cycles can be anywhere from about two to twelve years, with most cycles averaging six years in length. some business analysts use the business cycle model and terminology to study and explain fluctuations in business inventory and other individual elements of corporate operations. but the term "business cycle" is still primarily associated with larger (industry-wide, regional, national, or even international) business trends.