Correct option is B
Given:
15 men can complete the work in 30 days.
We need to find how many days 9 men would take to complete the same work.
Formula Used:
Men1×Days1=Men2×Days2
Solution:
Men1=15,Days1=30
Men2=9,Days2=?
Using the formula:
15×30=9×Days2450=9×Days2Days2=9450=50 days
Thus, 9 men would need 50 days to complete the work.