8. You start with 240 gallons if in march you use 40% (.4(240)=96) you used 96 gallons in march, leaving you with 144 gallons. If you then used 25% in April (.25(144)=36) you would have used 36 gallons leaving you with 108 gallons at the end of April.
9. If 2277 is 110% the number of 2013 to find what 2013 was you would divide by 110%(1.1)
2277/1,1=2070 at the end of 2013
If 2070 is 90% then we will want to divide by 90% (.9) to get the year before that
2070/.9=2300 so 2300 people were signed up in the year 2012
10. 57.5=p(250)
to solve this divide both sides by 250 to get p=.23
As for the different elements to the equation, there are various answers such as what percentage of people donated $250 if the average amount of money donate from each one is 57.5 although that may no be what you instructor is looking for. pretty much just make up something that sounds okay and you should be fine