Tony bought a number of shares of stock for $720. A month later the value of the stock increased by $8 per share, and he sold all but 20 shares and received $800. How many shares did he sell and at what price per share?
Lets say he had x shares
And the price of each share = y
Total value for all stocks = 720$ = xy
Thus our first equation is
xy= 720$
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After a month
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No. shares sold =x-20
rice of each share = y+ 8
Amount he received =(x-20)(y+8) = 800$
Thus our second equation is
(x-20)(y+8) = 800$
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Solve the two equations
x = 60 , y= 12