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For a fixed amount of work, the product of the number of workers and the days taken is:
AAlways increasing
BConstant
CAlways decreasing
DEqual to the number of days
Answer & Solution
Correct answer: B. Constant
1. Workers and days are in inverse proportion for a fixed job.
2. If one doubles, the other halves, leaving their product untouched.
3. That constant product measures the total work, in worker-days.
4. It is why 6 men for 10 days and 4 men for 15 days both represent 60 worker-days.
5. This constant is the quantity to compute first in almost every question of this kind.
_Source: NCERT Class 8 Maths, Ch 11 'Direct and Inverse Proportions', S11.3 Inverse Proportion_
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