Disha takes 12 hours to copy a 75-page manuscript, while Mohit can copy the same manuscript in 10 hours. How many hours will it take for them to copy a 150-page manuscript if they work together?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. hours.
Disha can copy a 75-page manuscript = 12 hours
Mohit can copy the same manuscript = 10 hours
So,
Disha can copy a 150-page manuscript = 12 × 2 = 24 hours
Mohit can copy a 150-page manuscript = 10 × 2 = 20 hours
So, the the total work = LCM of 24 and 20 = 120
Efficiency = Total work/Total time
Disha's efficiency = 120/24 = 5
Mohit's efficiency = 120/20 = 6
Total time = Total work/(sum of the efficiency of Disha and Mohit)
= 120/(5 + 6) = 120/11
= hours