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Looking forward to solving the problem of mathematical clocks and watches
1、

First of all, we must calculate the time when the two stitches overlap after two o'clock.

Then calculate the time when the two stitches overlap after five o'clock.

At two o'clock, the angle between the hour hand and the minute hand is 60 degrees.

1 hour, the hour hand goes 30 degrees, and the minute hand goes 360 degrees.

That is, the minute hand can walk 330 degrees more than the hour hand.

So it takes time from two o'clock to two stitches: 60 * 60/330 =120/11minute.

That is to say, Wang Tian starts at 2: 00 and 120/ 1 1.

Similarly:

At five o'clock, the angle between the hour hand and the minute hand is 150 degrees.

So it takes time from two o'clock to two stitches: 60 *150/330 = 300/11minute.

That is, Wang Tian ends at 5: 00 and 300/ 1 1.

Time: 5: 00 and 300/ 1 1: 00 -2: 00 and 120/ 1: 00 =3 hours and 180/ 1 minute.

2、

Similar to the above question

First, calculate the coincidence time of two stitches from 3 to 4 o'clock.

At three o'clock, the second needle is 90 degrees.

So it takes time from three o'clock to two stitches: 60 * 90/330 =180/11minute.

That is, Wang Lan starts at 3 o'clock, 180/ 1 1.

After finishing homework, the two needles form a straight line, that is, the angle is 180 degrees.

From coincidence to 180 degrees

Elapsed time: 60 *180/330 = 360/11min.

180/ 1 1+360/ 1 1=540/ 1 1

That is 3: 540/ 1 1 min.

Operation time: 540/11-180/1= 360/1min.