Correct option is C
Given:
Time taken by Y and Z together to complete the work = 20 days
Time taken by Z alone to complete the work = 60 days
Formula Used:
Total Work = Efficiency
Solution:
Let the total work = LCM of 20 and 60 = 60 unit
Efficiency of Y+ Z = 3 unit per day
Efficiency of Z = 1 unit per day
Efficiency of Y = 3-1 =2 unit per day
Time taken by Y to complete the same work =