I don't really understand what you're asking, but say you have the number 67,to find 23% of that number, you would multiply 67 by .23, you will then get whatever 23% of 67 is.
37 times 720 divided by 20 is 36 then you need gas to run the 5 other miles.
This is an exponential table
800 because 20*4*10=800 which means he works 80 weeks a month for 10 months