Question: On Sunday, December 22, four ships - W, X, Y, Z - started their series of winter cruises to various ports. Ship W left at 4:00 PM on Sunday, December 22, for a series of 8-days cruises to Mandva. * Ship X left at 4:30 PM on Sunday, December 22, for a series of alternating 11-days and 13-days cruises to Alibaug.
* Ship Y left at 5:00 PM on Sunday, December 22, for a series of 5-days cruises to Khihim.
* Ship Z left on Monday for a series of 7-days cruises.
Each ship is scheduled to return back early in the morning after the last day of the cruise and leave again late in the afternoon of the same day.
On how many days occasions between December 22 and February 28 will three ships be moored at the port?
Answer:
On no occasions (other than start date December 22) between December 22 and February 28,
three ships will be moored at the port.
Find out the days on when each ship will be in port:
* Ship W will be in port on days 1, 9, 17, 25, 33, 41, 49, 57 and 65.
* Ship X will be in port on days 1, 12, 25, 36, 49, 60 and 73.
* Ship Y will be in port on days 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, 51, 56, 61 and 66.
* Ship Z will be in port on days 1, 2, 9, 16, 23, 30, 37, 44, 51, 58 and 65.
From above data, it is clear that - on no occasion (other than December 22) will three ships be moored at the port.
Also, on 8 occasions, there will be 2 ships moored at the port.