SOLUTION: If 20 percent of nitrogen combined with the other elements. If 740 kg of nitrogen did not combine, how much did combine?

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Question 9902: If 20 percent of nitrogen combined with the other elements. If 740 kg of nitrogen did not combine, how much did combine?
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
NOTE: See last paragraph first. It's probably easier!! R^2

I think it might be a good idea to set up a ratio, using this information: If 20% (i.e., .20) combines, then 80% (i.e., .80) does NOT comine. Let x = amount that combines, which is what you need to find.

+%28combined%29%2F%28not_combined%29: .20%2F.80+=+x%2F740

Remember a%2Fb=c%2Fd means that a%2Ad=b%2Ac, so
.20%2F.80+=+x%2F740+

This reduces to 1%2F4+=+x%2F740 which means that
4x+=+740
x=740%2F4
x=+185 kg

Now that I think about this, there is probably an easier way to do this, like just realizing that for every part that combines there are 4 parts that do not combine. Therefore, the amount that combines is 1/4 of the amount that does not combine, and 1/4 of 740 = 185 kg. That would have been a lot easier. Oh well. Too late now.

R^2 at SCC