Answer:
He drove 27[tex]\frac{13}{31}[/tex] miles per gallon.
Step-by-step explanation:
15[tex]\frac{1}{2}[/tex] gas = 425 miles
[tex]\frac{31}{2}[/tex] gas = 425 miles
31 gas = 425 × 2
= 850 miles
1 gallon = 850 miles ÷ 31
1 gallon = 27[tex]\frac{13}{31}[/tex] miles
