Final answer:
To find the total number of gallons of gasoline in the car's tank after Mrs. Ruiz added fuel, we add the initial amount of gasoline to the amount she added. Mrs. Ruiz initially had 4(7)/(10) gallons of gasoline and added 3(9)/(10) gallons, resulting in a total of 86/(10) gallons of gasoline in the car's tank.
Step-by-step explanation:
To find the total number of gallons of gasoline in the car's tank after Mrs. Ruiz added fuel, we need to add the initial amount of gasoline to the amount she added.
Mrs. Ruiz initially had 4(7)/(10) gallons of gasoline, and she added 3(9)/(10) gallons.
To add these amounts, we can convert them into a common denominator and then add the fractions.
Converting 4(7)/(10) to an improper fraction, we get 47/(10). Converting 3(9)/(10) to an improper fraction, we get 39/(10).
Adding 47/(10) and 39/(10), we get (47+39)/(10) = 86/(10).
Therefore, there were 86/(10) gallons of gasoline in the car's tank after Mrs. Ruiz added fuel.