UGC NET Questions (Paper – 1)

Statements A, B and C are correct because they follow the standard work-rate model: daily work is reciprocal of time, combined rate is additive and rate and time are inversely related when total work is fixed. Statement E is also true, as time and work problems are common in competitive exams including UGC NET. Statement D is false, since doubling the number of workers at the same rate would halve the time, not double it. Hence, the combination that includes A, B, C and E and excludes D is correct.

Option A:
Option A is incomplete because although it lists three true statements, it omits E and therefore fails to acknowledge the practical relevance of time and work problems in exam contexts. Without E, the question’s aptitude orientation is underplayed.

Option B:
Option B is correct as it gathers all four true statements about how work rate is modelled and assessed in exams, and it rightly rejects D, which reverses the effect of doubling the workforce. This option matches the conceptual structure used in NET work-rate questions.

Option C:
Option C is wrong because it includes D, the incorrect statement about time doubling, and excludes A, missing the basic definition of one-day work. The presence of D makes the overall set invalid.

Option D:
Option D is incorrect since it excludes B and thus does not stress that combined work is the sum of individual works, while still omitting the false D. Even though A, C and E are true, leaving B out makes the description incomplete.

A is correct because one-hour work is the reciprocal of the total time needed. B is correct as an emptying pipe can be assigned a negative work rate. C is also correct since combined effect is the sum of filling and emptying rates with appropriate signs, and E is true because these problems are a direct application of time and work concepts. D is wrong because two filling pipes working together have a combined time less than either individual time; for 6 and 8 hours, the joint time is 24/7 hours, not 14 hours. Hence D only is the wrong statement.

Option A:
Option A correctly isolates D as the single incorrect statement, leaving the accurate descriptions of one-hour work, negative rates and time–work analogy intact. It reflects the usual modelling of pipes and cisterns problems in aptitude tests.

Option B:
Option B incorrectly treats both C and D as wrong, even though C correctly describes adding work rates with signs. By misclassifying C, this option fails the requirement to pick only wrong statements.

Option C:
Option C wrongly includes B as wrong along with D, despite B providing a standard way of modelling emptying actions with negative work. This misidentification makes the option invalid.

Option D:
Option D is incorrect because it also labels A as wrong, even though A properly defines one-hour work as the fraction 1/5. Thus it rejects a true statement while trying to catch the false one.

If a person completes the entire work in 8 days working at a constant rate, then each day they complete 1/8 of the total work. This follows from the idea that total work is taken as 1 and is divided equally among the number of days. The daily work rate is thus the reciprocal of the total time. Therefore, 1/8 is the correct fraction of work done in one day.

Option A:
1/6 would imply that the work is fully completed in 6 days, because 6 times 1/6 equals 1. However, the question clearly states that the work is completed in 8 days. Hence, 1/6 overestimates the daily work rate and is inconsistent with the given information.

Option B:
1/4 would mean completing the work in 4 days, since four days of work at this rate would make a full unit of work. This contradicts the stated time of 8 days. Therefore, 1/4 is not compatible with the conditions of the problem.

Option C:
The fraction 1/8 is correct because multiplying it by the total number of days, 8, yields 1, representing the entire work: 8 × 1/8 = 1. This reflects the standard unitary method used in time and work questions. Recognising that the daily rate is the reciprocal of total time simplifies many such problems on competitive exams.

Option D:
2/8 simplifies to 1/4, which, as explained earlier, corresponds to finishing the work in 4 days rather than 8. Using this fraction would contradict the given total time to completion. As a result, 2/8 is not the correct fraction of work done in one day in this scenario.

B gives the standard combined-rate formula. C is also correct: independent daily rates add. A is false because working together they finish faster than either alone, so the time is less than 6 days (and certainly not greater than 10). D is false because doubling workers halves time only under ideal assumptions, not “always”. E is false because different workers can have different speeds. Thus only B and C are correct.

Option A:
Option A is incomplete because it omits C, the general rate-addition rule for more than two workers.

Option B:
Option B is correct because it includes exactly the true rate principles (B and C) and excludes A, D and E, which are false generalisations.

Option C:
Option C is wrong because it includes A, which incorrectly claims the combined time is greater than 10 days.

Option D:
Option D is incorrect because it includes D, which is not universally true, even though B and C are true.