Correct Answer - Option 3 : 30 days
Given:
X, Y, and Z together can complete the work = 15 days
X and Y can complete the work = 30 days
Formula used:
W = E × T
(Where W = The work, E = The efficiency, and T = Time)
Calculation:
Let us assume Z alone can complete the work in X days
⇒ The efficiency of X, Y, and Z = \({1\over 15}\)
⇒ The efficiency of X and Y = \({1\over 30}\)
⇒ The efficiency of Z = \({1\over X}\)
⇒ \({{1\over 30}\ +\ {1\over X}}\ =\ {1\over 15}\)
⇒ By solving the value of X
⇒ X = 30 days
∴ The required result will be 30 days.
