Area question?

'The owner wants to use the field to plant potatoes in rows parallel to the AC edge. The first row will be on the AC line and the last row will be on BD line. In between, he will plant one row every 6 inches. Given that there are 36 inches in a yard, how many rows of potatoes will be planted?'

The answer is 901 but I don't understand why they've done 150 x 36 rather than calculating the entire area and then multiplying by 36??
Can anyone talk me through this question please?

This has nothing to do with area. The question merely calls on you to recognise that each of the 150 yards in the length contains six rows AND the field edge contains an extra row, making 150 x 6 +1 = 901 rows.

Okay makes sense but I would've thought the final row was included in the 150 yards..