"production"is non countable so "less than " should be used.
CDE Out
A Vs B
X less than Y
production less than harvest
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A is wrong because those refers to tons . But we need to compare harvest total in one year to harvest total in another year.

Less than in the start of phrase should be there so, D and E are out. however, after less than "that of" is required to make it parallel. "Those of" is wrong as it comes when noun is plural. "C' is also out.
But why "B" is right I dont know.

Anyone, please explain.

But in 'B' we are comparing production with the harvest, which might not be correct. Production with production will be ok.

It is B. 1979 rice production is compared with 1978 harvest. Hope it helps!

We only want to use "that of" or "those of" if we are comparing something *belonging* to something else:

The design of the new tablet is similar to that of its predecessor. (The design of one is similar to the design of the other.)
Jack wanted clothes similar to those of his friends. (He wants his clothes to be similar to his friends' clothes.)

In the above examples, it would be a big problem to get rid of the relative pronoun:

The design of the new tablet is similar to its predecessor. (The design is similar to the predecessor?)
Jack wanted clothes similar to his friends. (He wants his clothes to be similar to his friends?)

In B, we are correctly comparing the production in 1979 to the harvest in 1978. If we go with gmatfighter12's proposed phrasing, "less than that of," we have to ask what "that" stands for. If we say "less than that of the 1978 harvest," then "that" doesn't seem to stand for anything. If we say "less than that of 1978," the antecedent for "that" isn't entirely clear, although "production" seems like the most reasonable choice. E would then be clearer than the other wrong answer choices, but still not as clear as B.

Note that in my examples, it was very clear what "that" and "those" stood for. If we don't know what our pronouns stand for, we should probably replace them. In general, a specific noun is preferable to a vague pronoun (unless that specific noun is clearly wrong!).
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No, size makes no difference. We always use "fewer" for countable and "less" for uncountable. Here, we use "less" rather than "fewer" because we are comparing the overall size of production, rather than the specific number of tons. This generally happens with weights and measures. For instance, I would say "I weigh less than 200 pounds," not fewer, because I am talking about a measurement, not a group of things. I'd also say "I want less than 3 ounces of coffee" or "I have less than 5 feet of rope left." Sure, we can count pounds, ounces, and feet, but we are using them to talk about an amount, not a number. 3 ounces of coffee is a way of saying how much coffee you have, but we're not counting individual coffee beans. Similarly, in the original problem, we're not counting individual grains of rice; rather, we're measuring overall rice production.
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Dmitry Farber | Manhattan GMAT Instructor | New York


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thangvietnam, check above for the explanation given by Dmitry Farber from MGMAT. He has explained why use "Less" rather than "Fewer" to compare the measurements or weights.
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Thanks,
PraPon

VOTE: vote-best-gmat-practice-tests-excluding-gmatprep-144859.html
Tough RCs: Passage1 | Passage2 | Passage3 | Passage4 | Passage5 | Passage6 | Passage7

great, thank you, manhantan expert.

I am satisfied with oa but

In 1979 lack of rain reduced India's rice production to about 41 million tons, nearly 25 percent //less than those of the 1978 harvest.//

(A) less than those of the 1978 harvest

(B) less than the 1978 harvest

(C) less than 1978

(D) fewer than 1978

(E) fewer than that of India's 1978 harvest


but "less than the 1978 harvest" modify "production" or " 41 million tons" pls, help

THANK YOU expert,
do you have any tips for "few " and "less" , pls help