There are the two clocks A and B.
The clock A moves too slow by 1 minute in 2 hours and the clock B moves too fast by 2 minutes in 3 hours.
In the evening of one day, the clock A pointed 6:05 and the clock B pointed 6:00.
When setting the alarm of the clock B to 7:00, the bell of the clock B rang in the next morning.
Find the time which the clock A points at the time.
The clock A moves too slow by 1 minute in 2 hours and the clock B moves too fast by 2 minutes in 3 hours.
In the evening of one day, the clock A pointed 6:05 and the clock B pointed 6:00.
When setting the alarm of the clock B to 7:00, the bell of the clock B rang in the next morning.
Find the time which the clock A points at the time.
Answer
The ratio of speed is (360 minutes - 3 minutes) : (360 minutes + 4 minutes) = 357 : 364 = 51 : 52.
While B moves for 13 hours, A will follow only the 51/52 of it.
It is 13 × 51/52 = 51/4 hours = 12 hours and 45 minutes.
It was 6:05 in A and A moved for 12 hours and 45 minutes. 6:05 + 12 hours and 45 minutes = 18 hours and 50 minutes.
The time of A is 18:50 - 12:00 = 6:50.
6:50
Solution
According to the problem sentence, in 6 hours, A moves too slow by 3 minutes and B moves too fast by 4 minutes.
The ratio of speed is (360 minutes - 3 minutes) : (360 minutes + 4 minutes) = 357 : 364 = 51 : 52.
While B moves for 13 hours, A will follow only the 51/52 of it.
It is 13 × 51/52 = 51/4 hours = 12 hours and 45 minutes.
It was 6:05 in A and A moved for 12 hours and 45 minutes. 6:05 + 12 hours and 45 minutes = 18 hours and 50 minutes.
The time of A is 18:50 - 12:00 = 6:50.
