In a mixture of aluminum and zinc, there are 8 pounds of zinc for every 4 pounds of aluminum. If a total of 240 pounds of this mixture is created, how many pounds of aluminum are needed?
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this pattern comes up frequently
Can you explain more?
ratio 8:4 simplifies to 2:1 so aluminum is just a third of the total. pretty straightforward once you see it
yep, that simplify step is the whole trick. took me a sec to remember it though lol
same here, i almost plugged 8 and 4 straight into the total without reducing first
wait why is it not just 240/8? got 30 and it felt too easy
because the 8 and 4 are the ratio parts, not the whole. you have to add them together before dividing the total
thanks!
these mixture ratio ones always trip me up but this one was gentle. 80 it is
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.