The table shows the amount of gas, in gallons, a truck has left after it is driven at a constant rate for a certain number of hours.
Number of Hours Driven Amount of Gas Left
3
9
4
6
5
3
Which statement is true?
The truck initially has 
9
 gallons of gas, and each hour 
3
 gallons of gas are used.
The truck initially has 9 gallons of gas, and each hour 3 gallons of gas are used.
The truck initially has 
9
 gallons of gas, and each hour 
6
 gallons of gas are used.
The truck initially has 9 gallons of gas, and each hour 6 gallons of gas are used.
The truck initially has 
18
 gallons of gas, and each hour 
3
 gallons of gas are used.
The truck initially has 18 gallons of gas, and each hour 3 gallons of gas are used.
The truck initially has 
18
 gallons of gas, and each hour 
9
 gallons of gas are used.
The truck initially has 18 gallons of gas, and each hour 9 gallons of gas are used.