Work Efficiency — Prelims Strategy

Prelims Strategy

Identify whether the given numbers are completion times, efficiencies or amounts produced. Convert them to rates in a common work unit before combining workers. A convenient least common multiple can keep the arithmetic integral, but a whole-job unit of one is equally valid. Do not mix units within the same equation.

Mark a timeline whenever the team or working schedule changes. Calculate the work done in each interval, subtract it from the total and solve for the remaining time at the new rate. If a worker operates for only part of each day, adjust the contribution using actual working hours rather than treating attendance as full-time work.

For an efficiency percentage, write the rate ratio first and invert it to obtain the time ratio. Test answer options against basic bounds: two positive independent rates should finish sooner than either alone, and work completed cannot exceed the total before the claimed finishing point. Finally, distinguish total elapsed time from the time after a worker leaves, because both may appear as plausible numerical alternatives.