We can solve this problem step by step.

Part 1: Calculating the total cost for 3 orders of fries and 5 drinks

• The cost of one order of fries is $1.20.
• The cost of one drink is $0.96.

So, the total cost for 3 orders of fries and 5 drinks is:

$\text{Total cost} = (3 \times 1.20) + (5 \times 0.96)$

Now, calculating this:

$(3 \times 1.20) = 3.60$ $(5 \times 0.96) = 4.80$ $\text{Total cost for 3 fries and 5 drinks} = 3.60 + 4.80 = 8.40$

Thus, the cost for 3 orders of fries and 5 drinks is $8.40.

Part 2: Generalizing the cost for f orders of fries and d drinks

The total cost for f orders of fries and d drinks can be written as:

$\text{Total cost} = (f \times 1.20) + (d \times 0.96)$

This formula gives the total cost for any number of fries (f) and drinks (d).

Would you like any more details, or do you have any questions?

Here are 5 related questions:

1. How would the cost change if the price of fries or drinks increased?
2. What would the cost be for 4 orders of fries and 6 drinks?
3. Can you derive a similar equation if the price of fries and drinks were both 10% higher?
4. How would you solve for the number of drinks if you knew the total cost and the number of fries ordered?
5. How can this be expressed in matrix form?

Tip: Always double-check your arithmetic when solving these types of problems to avoid minor mistakes!