It seems there are missing values in your question, but I can walk you through the general approach.

Let:

• $t$ represent the total hours the Hernandez family traveled, and
• $g$ represent the number of tanks of gas they used.

To find how many hours each tank of gas allowed them to travel, you would divide the total hours by the number of tanks of gas: $\text{Hours per tank} = \frac{t}{g}$

To find how much of a tank of gas they will use if they drive for $h$ hours, you would divide the number of hours by the hours per tank: $\text{Gas used for } h \text{ hours} = \frac{h}{\text{Hours per tank}} = \frac{h}{\frac{t}{g}} = \frac{h \cdot g}{t}$

Once you provide the specific values for $t$ (total hours traveled) and $g$ (tanks of gas used), I can give you the exact numbers.

Would you like to give those values, or should I continue with these formulas?

Here are five questions for better understanding:

1. How many total hours did the family drive?
2. How many tanks of gas did they use during the trip?
3. How long do they plan to drive in the future?
4. Are there any specific fuel efficiency rates you're curious about?
5. Does the driving condition (e.g., city vs highway) impact their gas usage?

Tip: Always ensure you have all the necessary values (e.g., total time, number of tanks) to calculate with accuracy.