Question 1115446
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The cost of 6 mooncakes with two egg yolks + 5 mooncakes with one egg folk =  130.80 dollars


6*(x+2)                                    + 5x                            = 130.80


6x + 12  + 5x = 130.80

11x = 130.80 - 12 = 118.80  ========>  x = {{{118.80/11}}} = 10.80.


Hence,  one mooncake with one egg folk costs $10.80.


Then    one mooncake with two egg folk costs $12.80.
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Solved.