To finish a certain work, it will take 12 days by A and 15 days by B.
A and B jointly started to finish the work but B rested a number of days.
It took 8 days to finish the work.
How many days did B rest ?
The daily work load of A is 1/12 and B is 1/15.
For two persons, total daily work load is 1/12 + 1/15 = 3/20.
Since the work load at the time of working for eight days by two persons is set to 3 / 20 × 8 = 6/5.
The difference between 1 and 6/5 comes to the work load B rested.
1 - 6/5 = 1/5
It is (1/5) /(1/15)=3 days that B rested.
A and B jointly started to finish the work but B rested a number of days.
It took 8 days to finish the work.
How many days did B rest ?
Answer
3 days
Solution
The volume of this work is set to 1.
The daily work load of A is 1/12 and B is 1/15.
For two persons, total daily work load is 1/12 + 1/15 = 3/20.
Since the work load at the time of working for eight days by two persons is set to 3 / 20 × 8 = 6/5.
The difference between 1 and 6/5 comes to the work load B rested.
1 - 6/5 = 1/5
It is (1/5) /(1/15)=3 days that B rested.
