The percentage of families that were married couples with children between 1970 and 2000 is approximately 47.2 P(t) = 0.27 (1sts 4) where t is measured in decades, with t = 1 corresponding to 1970. (a) What percentage of families were married couples with children in 1970? In 1990? In 2000? (Round your answers to one decimal place.) in 1970 % in 1990 in 2000 (b) How fast was the percentage of families that were married couples with children decreasing in 1980? In 1990? (Round your answers to one decimal place.) in 1980 % per decade in 1990 % per decade