# SOLUTION: Lily mixed a 45% copper sulfate solution and a 25% copper sulfate solution to get 100 mL of a 31% copper sulfate solution. Haw many mL of the 25% solution did she use?

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 Question 386217: Lily mixed a 45% copper sulfate solution and a 25% copper sulfate solution to get 100 mL of a 31% copper sulfate solution. Haw many mL of the 25% solution did she use?Answer by stanbon(57407)   (Show Source): You can put this solution on YOUR website!Lily mixed a 45% copper sulfate solution and a 25% copper sulfate solution to get 100 mL of a 31% copper sulfate solution. Haw many mL of the 25% solution did she use? ------------------ Equations: Quantity Eq:::: x + y = 100mL Copper Eq::::: 0.25x+0.55y = 0.31*100 ----------------------------------------- Multiply Quantity by 55 Multiply Copper by 100 --------------------------- 55x + 55y = 55*100 25x + 55y = 31*100 --------------------------- 30x = 24*100 x = 80mL (amt. of 25% solution needed in the mix) ======================================================= Cheers, Stan H.