Ok so first we have 240 gallons of fuel in the tank. According to the table, in March the people used 40% of that fuel so we do 0.40 multiplied by 240 and we get...
96
now we take 96 and subtract that from 240 and we get...
144.
Now the table says the people used 25% of the fuel.
So now we multiply 0.25 by 240 and we get...
60.
Now we subtract 60 from 144 and we get...
84!!!