I’m studying for my Academic class and don’t understand how to answer this. Can you help me study?

1.John Jetison believes he would need $500,000 to retire today and keep his same lifestyle. If Jetison estimates he will retire in 20 years, how much should he put away each month to have the equivalent of $500,000 in 20 years if the interest he can earn is 5%? If the interest rate changes to 3%, what will Jetison need to save each month? Picture cash flows on a timeline and present it when providing your answer. Think about your own retirement; what would the timeline look like? In what ways could you better prepare for retirement? Answer in couple sentences

and then agree or disagree to a post below within 2-3 sentences

2.If John Jetison wishes to retire in 20 years with $500,000, he would need to save $1,216.45 a month if the interest he can earn is 5%. If John Jetison’s interest changes to 3%, he would need to save $1,522.99 a month to reach his goal of retiring with $500,000 in 20 years. I am 24 years old and I would like to retire by the age of 50 with 2 million dollars (I can dream :))