At the end of a journey 7/9 of the fuel tank of a car had been used and the remaining was 14 litres. How much fuel was in the tank at the beginning of the journey.

So 2/9 of the full tank remain,

(2/9)x = 14
x = 14(9/2) = 63 L

To determine how much fuel was in the tank at the beginning of the journey, we need to find the total capacity of the fuel tank.

Let's assume the total fuel capacity of the tank is "x" litres.

According to the information given, 7/9 of the fuel tank was used, leaving 14 litres remaining.

So, 7/9 of x litres = 14 litres.

To find the value of x, we need to isolate it on one side of the equation.

Multiplying both sides of the equation by (9/7), we have:

(9/7) * (7/9) * x = (9/7) * 14

Canceling out the common factors, we get:

x = 18

Therefore, the fuel tank had 18 litres of fuel at the beginning of the journey.

To find the amount of fuel in the tank at the beginning of the journey, you can use the given information that 7/9 of the fuel tank was used and the remaining fuel is 14 liters.

Let's assign a variable to represent the total fuel in the tank at the start of the journey. Let's call it "x".

According to the problem, 7/9 of the fuel tank was used. This means that (7/9)*x liters of fuel was used.

The remaining fuel after the journey is 14 liters. Therefore, the equation can be set up as follows:

x - (7/9)*x = 14

To solve this equation for x, we can simplify:

(2/9)*x = 14

Next, we'll isolate x by multiplying both sides of the equation by the reciprocal of (2/9), which is (9/2):

((9/2) * (2/9)) * x = (9/2) * 14

This simplifies to:

x = (9/2) * 14

Multiplying 9/2 by 14 gives us:

x = 63

Therefore, the amount of fuel in the tank at the beginning of the journey was 63 liters.