Critical Reasoning

A company plans to develop a protoype weeding machine that uses cutting blades with optical sensors and microprocessors that distinguish weeds from crop plants by differences in shade of color. The inventor of the machine claims that it will reduce labor costs by virtually eliminating the need for manual weeding.
Which of the following is a considerating in favor of the company's implementing its plan to develop the protoype?
A. There is considerable degree of variation in shade of color between weeds of different species
B. The shade of color of some plants tends to change appreciably over the course of their growing season.
C. When crops are weeded manually, overall size and leaf shape are taken into account in distinguishing crop plants from weeds.
D. Selection and genetic manipulation allow plants of virtually any species to be economically bred to have a distinctive shade of color without altering their other characteristics.
E. Farm laborers who are responsible for the manual weeding of crops carry out other agricultural duties at times in the growing season when extensive weeding is not necessary.

I had a difficult time choosing between B(bc if the shades change, then the machine would be helpful and D(could be helpful too)

A test of the National Weather Service's storm-detecting radar syhstems found that the 1957 system is 10times more reliable than the new computerized system. Therefore, the technology used in the radar system must be less sophisticated than the radar techn. used in the 1957 system.
The conclusion drawn above depends on which of the following quesitonable assumptions?
A. The reliability of storm detecting radar systems is determined by the frequency of breakdowns
B. The level of sophistication of the technology used in storm detecting radar systems can be determined from the reliability of the system
C. The reliability of storm-detecting radar systems is determined by their accuracy in predicting weather patterns
D. Computer hardware is now a key component of the new storm-detecting radar systems used by weather patterns
E. Most of the significant advances in storm-detecting radar systems technology were made in the 1950s

I'm just confused by the question...

jamesk486 wrote:A company plans to develop a protoype weeding machine that uses cutting blades with optical sensors and microprocessors that distinguish weeds from crop plants by differences in shade of color. The inventor of the machine claims that it will reduce labor costs by virtually eliminating the need for manual weeding.
Which of the following is a considerating in favor of the company's implementing its plan to develop the protoype?
A. There is considerable degree of variation in shade of color between weeds of different species
B. The shade of color of some plants tends to change appreciably over the course of their growing season.
C. When crops are weeded manually, overall size and leaf shape are taken into account in distinguishing crop plants from weeds.
D. Selection and genetic manipulation allow plants of virtually any species to be economically bred to have a distinctive shade of color without altering their other characteristics.
E. Farm laborers who are responsible for the manual weeding of crops carry out other agricultural duties at times in the growing season when extensive weeding is not necessary.

I had a difficult time choosing between B(bc if the shades change, then the machine would be helpful and D(could be helpful too)

I'd vote for D. It mentions that plants can be given a distinctive shade
of color and so the weeding machine should be able to "weed out" the
weeds from the plants.

B leads us to believe that the shade of color of the plant can be at-times
the same as that of the weed. We don't know what it will be at any
point of time and so cannot use color to weed out.

jamesk486 wrote:
A test of the National Weather Service's storm-detecting radar syhstems found that the 1957 system is 10times more reliable than the new computerized system. Therefore, the technology used in the radar system must be less sophisticated than the radar techn. used in the 1957 system.
The conclusion drawn above depends on which of the following quesitonable assumptions?
A. The reliability of storm detecting radar systems is determined by the frequency of breakdowns
B. The level of sophistication of the technology used in storm detecting radar systems can be determined from the reliability of the system
C. The reliability of storm-detecting radar systems is determined by their accuracy in predicting weather patterns
D. Computer hardware is now a key component of the new storm-detecting radar systems used by weather patterns
E. Most of the significant advances in storm-detecting radar systems technology were made in the 1950s

I'm just confused by the question...

First sentence talks about reliability. Second sentence draws a conclusion
on sophistication. The assumption should hence link reliability and
sophistication.

B correctly links sophistication with reliability.

For the first one I'd also vote for D. It's the only one that might help their case for the machine. The fact that shades change over the growing system doesn't really help much; the important consideration is whether the machine can accurately tell the difference between all crops and all weeds. If we can make the crops distinct, as D suggests, then we should be able to have the machine tell the difference.

Jayhawk's point on the second arg. is spot-on. This pattern of Analogy is pretty common on the GMAT, and you should keep your eye out for it. Any time an argument compares two things, the argument is assuming that the two things are similar enough to be validly compared. In this case there is no information given to indicate that the reliability of the system has anything to do with the sophisitication of the equipment.

IMO:

D for first one.

B for second one.

Thanks.