If solution A contains 30 percent mercury and solution B has 15 percent mercury, what will be the percentage of mercury in the mixture when 10 ounces of solution A are combined with 20 ounces of solution B?
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thanksss
greatt question!
Weighted average question, love these. Just remember B is twice as much as A so it pulls the result toward 15.
yeah this is why the answer isnt just halfway between 30 and 15, the weights matter
Got it right but I almost picked halfway between 30 and 15 out of habit. The 10 vs 20 ounces is the whole trick here.
same lol, good thing I reread the amounts
thanks, helpful reminder that the answer has to sit between 15 and 30 so two of the choices are instantly out.
wait how do you know which side it leans toward though?
What it tests
Your ability to reason about weighted averages and the composition of mixtures.
Common trap
Averaging the percentages of two solutions without weighting by their volumes.