In 2007, 60,000 residents of Rochester suffered from coronary heart disease (CHD). Assuming the population of Rochester in 2007 was 500,000. (B1) What was the prevalence of CHD in Rochester in 2007? Give your answer as a proportion and explain the tour answer. (B2)What was the prevalence per 1,000 people (out of 1,000 people, how many would have CHD)? Explain your answer.