



 
Hi Trina, You have 2500 mL of an fluoride/water solution that is 0.91% acid and thus you have
You want to add x mL of 49% acid/water solution. These x mL are composed of
Hence in total you have
The total volume of liquid is (2500 × 0.0091 + x × 0.49) + (2500 × 0.9909 +x × 0.51) mL (call this amount Q). The goal is for P to be 1.40% of Q. Solve for x. Harley  


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