Question 1207698
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Hi
Selena and Ella shared a sum of money. When Selena's share increased from 500 to 620 dollars, the amount of Ella's share decreased by 20%. How much was Ella's share at first. 

Let Ella's ORIGINAL/Old amount be E
Then Ella's NEW/Altered amount = E - 120
Ella's NEW/Altered amount decreased by 20%, or from 100% to 80% (.8)

                      We then get: E - 120 = .8E 
                                     - 120 = .8E - E
                                     - 120 = - .2E
<font color = red><font size = 4><b>Original/Old amount Ella had</font></font></b>, or {{{highlight_green(matrix(1,7, E, "=", (- 120)/(- .2), "=", (-"$1,200")/(- 2), "=", highlight("$600"))))}}} </pre>