Pipes cisterns, Work time Sample Question

The given question is a work time question and tests your ability to relate to the relation between the number of days it takes two people to do a task to their efficiency of completing the task.

Question 1

Ram completes 60% of a task in 15 days and then takes the help of Rahim and Rachel. Rahim is 50% as efficient as Ram is and Rachel is 50% as efficient as Rahim is. In how many more days will they complete the work?

1. 
   
   
2. 
   
   
3. 
   
   
4. 
   
   
5. None of these

Correct choice is (3). Correct Answer is

Explanatory Answer

Ram completes 60% of the task in 15 days.
i.e., he completes 4% of the task in a day.

Rahim is 50% as efficient as Ram is.
Therefore, Rahim will complete 2% of the task in a day.

Rachel is 50% as efficient as Rahim is
Therefore, Rachel will complete 1% of the task in a day.

Together, Ram, Rahim and Rachel will complete 4 + 2 + 1 = 7% of the work in a day.
They have another 40% of the task to be completed.
Therefore, they will take more days to complete the task.