Answer:
The answer is correct, here's why:
Step-by-step explanation:
Dr. Silva's tank holds 15[tex]\frac{7}{8}[/tex] gallons of gas.
She added 11.55 gallons to her tank to fill it up.
This means she must have had 5[tex]\frac{13}{40}[/tex] gallons to start with because 5[tex]\frac{7}{8}[/tex] - 11.55 = 5[tex]\frac{13}{40}[/tex]