Answer:
standard form : 2x + y = -2
G = gallons d = days
10g = 3d
?g = 1d
1g = ?d
-------------
for gallons in a day, divide 10g = 3d by 3
d = 10/3 gallons
3 and 1/3 gallons in a day
---------------
for days per gallon, divide 10g = 3d by 10
g = 3/10 days
1 gallon lasts 3/10 of a day
The answer is 2 and would you like an explanation