Question 637573
You are given a prescription for 100 mL of a 30% hydrochloric acid solution. The pharmacy carries 90% hydrochloric acid solution. How many mL of the concentration solution are needed to fill this prescription?
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let x=amt of the concentration solution needed to fill this prescription
90x=30%*100
.9x=30
x=30/.9
x=3+1/3 
amt of the concentration solution needed to fill this prescription=3+1/3 mL