Let Xiao Ming and the teacher's speed be V 1 and V2 respectively.
According to this proposal:
V 1(4/V2+8)=4
Simplify the above formula: V2-V 1=2V 1V2.
V1=1/4km/min
V2 =1/2km/min
Then the time for the teacher to chase for the first time is:
4/( 1/2)=8 minutes
The time it takes the teacher to catch up with Xiao Ming for the first time to catch up with Xiao Ming for the second time is:
4*2/( 1/2- 1/4)=32 minutes.
So the time is 10: 56 a.m.
By the way, classmate, the topic "I was just 8 kilometers away from home when I caught up for the second time" is probably "I was just 8 kilometers away from home when I caught up for the second time", but it doesn't have much impact on this problem, and it can be worked out without that condition. However, under this condition, the results can be obtained faster and the amount of calculation is smaller.
I hope I can help you in time. You should still be in primary school or junior high school. This seems to be a competition question. Generally, this kind of problem has skills and no calculation. You can ask your good classmates about their skills.
Study hard. Oh, come on ~o(∩_∩)o ...