at an amusement park, children are charged an entrance fee of $20 plus $3 per ride and adults are charged an entrance fee of $28 plus $4 per ride. Identify your variable with a 'let' statement and write expressions for both children and adults that represent the cost for each group.

The american academy of pediatrics wants to conduct a survey of recently graduated family practitioners to assess why they did not choose pediatrics for their specialization. provide a definition of the population, suggest a sampling frame, and indicate the appropriate sampling unit.