Clock A is delayed at a rate of 6 minutes to 1 hour.
Clock B proceeds at a rate of 6 minutes to 1 hour.
Both clocks are set at correct time of 1:00.
The angle between the long hand and the hour hand of clock A became 90 degrees for the first time from 1:00.
Then what time o'clock, minutes and seconds is clock B?
Answer
1 o'clock 26 minutes and 40 seconds
Solution
In one hour , A advances 60 - 6 = 54 minutes, B advances 60 + 6 = 66 minutes.
The speed ratio of A and B is 54 : 66 = 9 : 11.
It takes (30 + 90)/(6 - 0.5) = 240/11 minutes by clock A when the angle between the long hand and the hour hand of A becomes 90 degrees for the first time.
Then the time of clock B is 240/11 × 11/9 = 78/3 minutes = 26 minutes and 40 seconds.
