Let's go through the problem step-by-step to determine how much petrol Tony uses for his trip.
1. Determine the distances traveled:
First, Tony drives 13 miles in 13 minutes. We'll need to convert his additional driving time from 1 hour 24 minutes into hours:
[tex]\[ 1 \text{ hour } + \frac{24 \text{ minutes}}{60} = 1 + 0.4 = 1.4 \text{ hours} \][/tex]
Now, using his average speed of 68 mph, we can calculate the distance he covers in this time:
[tex]\[ \text{Distance} = \text{Speed} \times \text{Time} \][/tex]
[tex]\[ = 68 \text{ mph} \times 1.4 \text{ hours} \][/tex]
[tex]\[ = 95.2 \text{ miles} \][/tex]
Next, we sum up the two distances to get the total distance Tony drives:
[tex]\[ \text{Total Distance} = 13 \text{ miles} + 95.2 \text{ miles} \][/tex]
[tex]\[ = 108.2 \text{ miles} \][/tex]
2. Determine the fuel efficiency:
According to the table, if Tony drives at a speed of more than 65 mph, his car achieves 40 miles per gallon (mpg). Since he was driving at 68 mph, his car’s fuel efficiency for the majority of his journey would be 40 mpg.
3. Calculate the fuel used:
To find out the amount of petrol Tony uses, we'll divide the total distance by the fuel efficiency:
[tex]\[ \text{Fuel Used} = \frac{\text{Total Distance}}{\text{Miles per Gallon}} \][/tex]
[tex]\[ = \frac{108.2 \text{ miles}}{40 \text{ mpg}} \][/tex]
[tex]\[ = 2.705 \text{ gallons} \][/tex]
Therefore, Tony uses approximately [tex]\(2.705\)[/tex] gallons of petrol for his trip.
