To represent Lawrence's purchases, we can break the problem into two parts:

1. Morning purchases: Lawrence buys a certain number of boxes of candy at $4 per box.
2. Later purchases: He buys more boxes of candy at $6 per box.

Let:

• $t_1$ be the number of boxes Lawrence purchased in the morning (at $4 per box).
• $t_2$ be the number of boxes Lawrence purchased later (at $6 per box).

The total cost of his purchases is:

$4t_1 + 6t_2$

If $t$ represents the total number of boxes of candy Lawrence purchased, then:

$t = t_1 + t_2$

Thus, the total cost expression for Lawrence's candy purchases is:

$4t_1 + 6t_2$

Would you like more details on how to manipulate or expand this equation? Here are 5 related questions:

1. How can we solve for $t_1$ and $t_2$ if we know the total cost Lawrence spent?
2. What if the total number of boxes purchased, $t$, is given? How can we adjust the expression?
3. How would this change if Lawrence got a discount on the second purchase instead of a price increase?
4. What if Lawrence buys in bulk, say 10 boxes at once, how would that impact the calculation?
5. Can you generalize the formula for any two different prices per box?

Tip: When breaking down costs, separating the variables by time or price changes helps keep equations manageable.