In the twomonth period June 1July 31 2011 Hess Corp HES stoc

In the two-month period June 1–July 31, 2011, Hess Corp. (HES) stock decreased from $80 to $70 per share, and Exxon Mobil (XOM) stock decreased from $83 to $80 per share.† If you invested a total of $21,490 in these stocks at the beginning of June and sold them for $20,500 at the end of July, how many shares of each stock did you buy? HES shares XOM shares

Solution

Solution:

80h + 83e = 21,490

70h + 80e = 20,500

multiply first equation by 70, second equation by -80

5600h + 5810e = 1,504,300

-5600h - 6400e = -1,640,000
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-590e = -135,700

e = 230

By using first equation

80h + 83(230) = 21,490

80h = 2400

h = 30

By using second equation

70(30) +80(230) = 20,500

2100 + 18,400 = 20,500

20,500 = 20,500 checks.

Therefore You bought 30 shares of Hess

and 230 shares of Exxon Mobil.