The Information Below Describes the Real GDP Per Capita for the Country

The information below describes the real GDP per capita for the country of Bedrock for the period of 1975 to 1991.
a.If a new business cycle began in 1975, how long was this cycle?
b.The peak occurred in which year? The trough occurred in which year?
c.How long was the expansion? How long was the contraction?
$$\begin{array} { | c | c | } \hline \text { Year } & \text { Real GDP per Capit-a } \\\hline 1975 & 6,000 \\\hline 1976 & 6,300 \\\hline 1977 & 6,700 \\\hline 1978 & 7,200 \\\hline 1979 & 7,850 \\\hline 1980 & \mathbf { 8 , 2 5 0 } \\\hline 1981 & \mathbf { 8 , 4 5 0 } \\\hline 1982 & \mathbf { 8 , 5 5 0 } \\\hline 1983 & \mathbf { 8 } , 575 \\\hline 1984 & \mathbf { 8 } , 510 \\\hline 1985 & \mathbf { 8 } , 370 \\\hline 1980 & \mathbf { 8 } , 100 \\\hline 1987 & 7,950 \\\hline 1988 & 7,925 \\\hline 1989 & 7,960 \\\hline 1990 & \mathbf { 8 } , 035 \\\hline 1991 & \mathbf { 8 } , 155 \\\hline\end{array}$$