A builder combines cement, water, sand, and gravel in a weight ratio of 1 : 2 : 5 : 2 to create concrete. How many pounds of sand are required to produce 40 pounds of concrete?
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Thank you very much!
thanks!
thanks, this was a nice easy one to warm up with
fr, ratio problems are free points if you just add the parts first
wait why is the answer 20 and not 10? i added the parts and got 10 total... am i supposed to multiply by something?
you added the ratio numbers to get the total parts, but then you still have to scale the sand portion to the 40 lbs. don't stop at the sum
ohhh i see it now. i thought the sum WAS the answer lol. thanks
The sand ratio is 5 out of the total parts, so sand is the biggest share — that's why the answer feels large compared to the others.
pretty straightforward for sub-505. add the 4 numbers, then set up the sand fraction equal to x over 40
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.