In the U.S., the emissions limit for carbon monoxide in motorcycle engine exhaust is 12.0 g CO per km driven. What is this limit expressed in milligrams per mile (mg/mi)?

1 Answer
anor277
Sep 13, 2015

This sounds like an old routine where the speed of light was expressed with the units," furlongs per fortnight ". There are 12,000 mg in 12 g, and 0.6213 miles in a km.

Explanation:

1 km = 0.6213 miles.

So #12.0# #g# #km^-1# = #12.0# #g# #xx 1000# #mg# #g^-1# #km^-1# = #12,000# #mg# #cancel(km^-1)# #xx# #0.6213# #cancel(km)# #mi^-1#, which is what? About #7.5# #xx# #10^3# millgrams per mile? Check this please because I'm too lazy to find a calculator.

I'm sorry to have abbreviated mile to #mi# (I did this because #m# = metre!), but if you do the calculation you will get an answer in "milligrams per mile". But why would you want to do so?

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