# SOLUTION: A service station wishes to mix 40 L of a 78% antifreeze solution. How many litres of a 75% solution and a 90% solution should be used in forming the mixture? ( using two unknowns,

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 Question 115179: A service station wishes to mix 40 L of a 78% antifreeze solution. How many litres of a 75% solution and a 90% solution should be used in forming the mixture? ( using two unknowns, write two equations and solve.)Answer by checkley71(8403)   (Show Source): You can put this solution on YOUR website!.9X+.75(40-X)=40*.78 .9X+30-.75X=31.2 .15X=31.2-30 .15X=1.2 X=1.2/.15 X=8L OF 90% IS NEEDED. 40-8=32L OF 75% IS NEEDED. PROOF .9*8+.75*32=40*.78 7.2+24=31.2 31.2=31.2