an object is placed at a distance of 20cm from concave lens of focal length 20cm . at what distance is the image formed from the lens?also find the magnification of the image​

The hypothetical island country of gilder lies in the mediterranean sea off the coast of france. demographers have studied gilder for the past 50 years. at the beginning of the study, gilder had a population of 20 million. the demographers have measured birth and death numbers, as well as immigration and emigration numbers, as shown in the data table. from the data, calculate the population of gilder for each 10-year period by filling in the population (no) and population (nt) columns in the data table. use this formula to do your calculations: population size: nt = no + (b + i) – (d + e)initial population = 20,000,000