<PRE><B>Question 630914</B>
one of the two watches gains 12 seconds in 18 days and the other loses 20 seconds in 30 days.
 If the watches were together at noon on a certain day, how many minutes apart would they be 90 days later?
:
Find how many seconds gained or lost one day
1st watch: 12/18 = +2/3 sec per day
2nd watch: 20/30 = -2/3 sec per day
:
{{{2/3}}}*90 = + 60 sec
{{{2/3}}}*90 = - 60 sec
--------------------------subtract to find difference
Total dif: 120 sec, which is 2 minutes
:
</PRE>