Answer:
18 gallons
Step-by-step explanation:
Let x represent a full tank, then
[tex]\frac{1}{5}[/tex] x + 9 = [tex]\frac{7}{10}[/tex] x
Multiply through by 10 to clear the fractions
2x + 90 = 7x ( subtract 2x from both sides )
90 = 5x ( divide both sides by 5 )
18 = x
The tank holds 18 gallons
