Question

startingdate=23may duration=25days finishingdate=?

Answer 1

The finishing date will be at 17 june
according to me.
Hope it helps!

Answer 2

If a certain event starts on 23 rd of may, and continues for 25 days, then it will end on 18th June,but only if  23rd may itself is not included in those 25 days. Or else if 23rd may in included too, the event will end on 17th June.