Ralph spends $5.25 on corn seed packets and each packet costs $1.75, we know that he buys 3 packets of seeds (5.25 / 1.75 = 3).
Since each packet contains 25 seeds, Ralph has a total of 3 x 25 = 75 seeds.
To find the greatest number of seeds that Ralph can plant in each row, we need to divide the total number of seeds by the number of rows:
75 seeds / 5 rows = 15 seeds per row
Therefore, Ralph can plant a maximum of 15 seeds in each row.