There is an accumulating difference of 2.5 seconds per day. You want that to equal 43,200 sec (one-HALF day) before the watches agree again (forget about AM/PM differences).
43,200 sec/2.5 (sec/day) = 17,280 days (47.3 years!).
My watch is 1 second fast each hour, and my friend's is 1.5 seconds slow each hour. Right now they show the same time. When will they show the same time again?
4 answers
How did you get that?
What's the way ?
The formula and the logic are explained in my answer. Each day one watch gets 2.5 seconds ahead of the other. You have to calculate how many days it takes for the difference to equal 12 hours. Divide 12 hours (in seconds) by 2.5 seconds per day.