Question 1138776
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The condition means that Luis has 5x stickers, while Cameron has 2x stickers, where x is some number, which is 
the common measure of the two amounts.


From the condition,  


    5x - 2x = 15,


which implies


    3x = 15  and  x = 15/3 = 5.


Thus Luis has 5*5 = 25 stickers, while Cameron has 2*5 = 10 stickers.
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