we know that
the car gets 18 miles per -----------> 1 gallon of gasoline
so
for 543 miles ---------------------> x gallons of gasoline
by proportion
543/18=x/1---------->x=543/18------->x=30.17 gallons
therefore
the answer is
30.17 gallons
5x-7y=14
-5x -5x
^
Subtract 5x from both sides
-7y=-5x+14
Divide by -7 by all of the numbers
y=-5/7x-2
I'm not all that familiar with that sort of representation, but I guess 3 3/4 = 15/4 and 2 1/6 = 13/6.
You will simply have to multiply the time spent walking, 13/6 hours, by the average distance traveled on an hourly basis, 15/4 km/h.
(13*15)/(4*6) = 195/24 = 8,125 km
5 offices = x offices
6 hours 12 hours
quick math shows that it's 10 offices
