Answer:
Cost of smaller box is $6.00 and cost of larger box is $18.00
Explanation:
We are given the following information in the question:
Let x be the cost of small boxes and y be the cost of larger fruit boxes.
Eric sold 25 small boxes and 14 large boxes for $402.00
This can be written in the form of expression:

Amanda sold 21 small boxes and 12 large boxes for $342.00
This can be interpreted with the expression:

Now, we have two equations in two variables. Thus, solving these equations with the help of substitution method:

Solving this equation, we have x= 6.
Putting this value of x in any of the equation, we get,

Therefore, cost of smaller box is $6.00 and cost of larger box is $18.00