Answer:
[tex]140\\[/tex] $
Step-by-step explanation:
Let the original price of US coin be "X"
The mark up in the price of US coin [tex]= 50 \\[/tex] %
Price of US coin after mark up
[tex]= X + ( \frac{50}{100} X)\\= 1.5 X\\[/tex]
[tex]1.5 X = 210\\X = \frac{210}{1.5} \\= 140\\[/tex]$
