Question 1091500

a)  If a ton (2000lbs) is $4540000 then one bill is  2000lbs/($4540000/$5) = 0.002203 lbs per $5 bill (0.03524 oz  or 1.00 gram).

b) Since a ton is only $4540000 in $5 bills, if we were to round up to $5 million worth of $5 bills, that would weigh about (500/454)*2000lbs or about 2200 lbs.   A reasonable estimate of the weight in $20 bills is about one quarter of that: (1/4)(2200 lbs) or 550lbs.   Who can carry around a 550lb briefcase?   [ Even if there were a person who could carry it, the SIZE of the briefcase would be very cumbersome. ]  
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I just googled for the size of $5 million in $20's and found this:
https://www.algebra.com/algebra/homework/proportions/Proportions.faq.question.977017.html