- A40 days40 दिन
- B50 days50 दिन
- C60 days60 दिन
- D70 days70 दिन
Show answer
Concept: Take total work = LCM of days; subtract efficiencies.
- Work = LCM(20, 30) = 60 units.
- P + Q = 3 units/day; Q = 2 units/day.
- P = 1 unit/day → 60 days.
Trick: 1/P = 1/20 − 1/30 = 1/60 → 60 days.
Answer: (C) 60 days
अवधारणा: कुल कार्य = दिनों का LCM; क्षमताएँ घटाएँ।
हल:
- कार्य = LCM(20, 30) = 60 इकाई।
- P + Q = 3 इकाई/दिन; Q = 2 इकाई/दिन।
- P = 1 इकाई/दिन → 60 दिन।
ट्रिक: 1/P = 1/20 − 1/30 = 1/60 → 60 दिन।
उत्तर: (C) 60 days
