The gas tank of Alberto's car holds a total of 42 liters of gas. At the beginning of the week, Alberto's car has 35.8 liters of gasoline in its tank. He uses 28.6 liters of gasoline during the week. Then he completely fills the tank with gas. How many liters of gas does Alberto buy?

Answer: he bought 34.8 liters of gas.

Step-by-step explanation:

Let x represent the number of liters of gas that Alberto bought.

At the beginning of the week, Alberto's car has 35.8 liters of gasoline in its tank. He uses 28.6 liters of gasoline during the week. This means that the number of liters of gas left would be

35.8 - 28.6 = 7.2

Then he completely fills the tank with gas. If the gas tank of Alberto's car holds a total of 42 liters of gas., it means that

x + 7.2 = 42

x = 42 - 7.2

x = 34.8 liters

34.8 liters

Step-by-step explanation:

He has 35.8 liters.

He uses 28.6 liters.

Now that tanks has 35.8 liters - 28.6 liters = 7.2 liters

The capacity of the tank is 42 liters, and he has only 7.2 liters.

The fill up will be 42 liters - 7.2 liters = 34.8 liters