In the past 160 years,our average life expectancy has increased at a rate of about per year.

Question

Quizplus · Accepted Answer

According to the statement, the average life expectancy has increased over the past 160 years. To find the rate of increase per year, we can divide the total increase by the number of years. If we assume an initial average life expectancy of 40 years (a reasonable estimate for 160 years ago), and a current average life expectancy of 80 years, the total increase would be 40 years. Dividing this by 160 years yields an increase of 0.25 years per year, or 3 months. Therefore, the best choice is A.

In the Past 160 Years,our Average Life Expectancy Has Increased