# Using “decrease by” and percents

I just read an article which described congestion on a particular line in Japan. Currently the trains are running at 200% capacity, but larger trains were introduced and "the crowding was reduced by ten percent". Later they say that "the trains are now crammed to just 190% capacity".

My question is: shouldn't reducing 200 percent by 10 percent yield 180 percent?

EDIT: Apparently the question is being treated as a math question. I don't really see it this way. Unless the original value is known, both answers (190% and 180%) could be correct. But, for some reason in case of this article it is obvious to the commenters that the correct answer os 190%.

EDIT2: Below is an excerpt from the article:

...trains were introduced to the line, and officials are hoping the new carriages, which are a whole 15cm wider, will reduce crowding by ten percent.

• No. All percentages are on the basis of 'percent of carrying capacity'. – Kris Jul 3 '13 at 6:03
• Why the downvote? – buskila Jul 3 '13 at 6:06
• The question is not about the English language, but probably math. See my comment above. – Kris Jul 3 '13 at 6:07
• The question is about the English language and your comment only proves it. How did you come to the conclusion that "all percentages" are on the bases of 'percent of carrying capacity'? Mathwise it could be either. – buskila Jul 3 '13 at 6:16

[This is likely to be too long for a comment...]

Either the question is about maths, or it's about English. You have asked about the maths; how they get to a result of 190%. That's off-topic.

So if we ignore that and assume it is about English, you can't apply the maths to get 180%.

Trains were 200% loaded; larger trains allowed that to get down to 190%. The difference is 10% of the current carrying capacity, not the original carrying capacity. It's not how one would normally do the maths, but then we're not discussing maths here, are we?