Sal Khan
$1 went a lot further in 1900 than today (you could probably buy a good meal for the family for $1 back then). Why? And how to we measure how-more-expensive-things-have-gotten (i. e. , inflation)? Source: Khan Academy (www.khanacademy.org), used under the Creative Commons Attribution-NonCommercial-ShareAlike (CC BY-NC-SA) license. All Khan Academy content is available for free at www.khanacademy.org. Khan Academy does not endorse the World Public Library.
Read this work at the World Public Library (library card needed).