Swagatalakshmi wrote:
Source : GMATPrep Default Exam Pack
Which of the following most logically completes the argument?
A new machine for harvesting corn will allow rows to be planted only fifteen inches apart, instead of the usual thirty inches. Corn planted this closely will produce lower yields per plant. Nevertheless, the new machine will allow corn growers to double their profits per acre because ________.
(A) with the closer spacing of the rows, the growing corn plants will quickly form a dense canopy of leaves, which will, by shading the ground, minimize the need for costly weed control and irrigation
(B) with the closer spacing of the rows, corn plants will be forced to grow taller because of increased competition for sunlight from neighboring corn plants
(C) with the larger number of plants growing per acre, more fertilizer will be required
(D) with the spacing between rows cut by half, the number of plants grown per acre will almost double
(E) with the closer spacing of the rows, the acreage on which corn is planted will be utilized much more intensively than it was before, requiring more frequent fallow years in which corn fields are left unplanted
Rows will be planted 15 inches apart, not 30. So in the same area, one could theoretically plant almost twice the number of plants. But if plants are this close, their yields (per plant) will reduce. So we would think that the overall yield may increase but will not double.
Nevertheless, the author expects the PROFIT to double (mind you, not the yield).
Since profit depends on revenue as well as cost and revenue is expected to increase somewhat, the chances of profit doubling increase if cost is reduced too.
We need to find something that explains why profit will double (mind you, profit can double even if revenue doesn't double say revenue goes up from $100 to $150 and cost stays the same at $50. The profit goes up from $50 to $100)
Let's see which option provides us with support for profit doubling.
(A) with the closer spacing of the rows, the growing corn plants will quickly form a dense canopy of leaves, which will, by shading the ground, minimize the need for costly weed control and irrigation
This gives us reasons for why the cost would decrease. This gives good support to the conclusion that profit will double. Revenue will likely increase and cost will decrease. Certainly looks like profit will get a big push.
(B) with the closer spacing of the rows, corn plants will be forced to grow taller because of increased competition for sunlight from neighboring corn plants
If anything, this seems to say that the plants will withdraw more nutrition from the soil (perhaps explains why yield will reduce). It doesn't explain why profit may double.
(C) with the larger number of plants growing per acre, more fertilizer will be required
This is increasing the cost hence reducing profit, not increasing it.
(D) with the spacing between rows cut by half, the number of plants grown per acre will almost double
This is something we can already infer from the given data. If rows are planted at half the distance, we can plant an extra row between every two rows and hence, almost doubling the number of plants. But we are also given that the yield will decrease. The option doesn't help explain why profit may double.
(E) with the closer spacing of the rows, the acreage on which corn is planted will be utilized much more intensively than it was before, requiring more frequent fallow years in which corn fields are left unplanted
Out of scope. We are talking about the yield in the year when the crop is planted.
Answer (A)