Final answer:
By setting up a system of linear equations based on the sales of Kristin and Kathryn, we find that one small box of grapefruit costs $9 and one large box costs $19 (option A).
Step-by-step explanation:
To solve the problem of finding the cost of one small box of grapefruit and one large box of grapefruit based on Kristin and Kathryn's sales, we can set up a system of linear equations. Let's denote the cost of a small box as s, and the cost of a large box as l.
Kristin's sales: 2s + 6l = $132 (1)
Kathryn's sales: 10s + 11l = $299 (2)
Multiplying equation (1) by 5 gives us 10s + 30l = $660. By subtracting equation (2) from this, we eliminate s and can solve for l:
19l = $361
l = $19 (after dividing both sides by 19)
Substitute l = $19 into equation (1):
2s + 6(19) = $132
2s + $114 = $132
2s = $18 (after subtracting $114 from both sides)
s = $9 (after dividing by 2)
Therefore, the cost of one small box of grapefruit is $9, and one large box of grapefruit is $19.