Simple Question, just need help establising second formula(adsbygoogle = window.adsbygoogle || []).push({});

Premium gasoline sells for 78.9/L. Regular gas sells of 71.9/L. To boost sales, a middle octane gasoline is formed by mixing premuium and regular. If 1000 L of this middle octane gas is prodcued ,and is sold at 73.9/L, then how much of each type of gasoline can you assume was used in the mixture. (units are in cents)

i got my first formula

x + y = 1000

its the second formula that confuses me

this is my incorrect one

78.9 x + 71.9 y = 73.9 (1000)

help

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# Homework Help: Using linear Systems to Solve Problems

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