Xiao Li walked home from school, 3 kilometers an hour. When Xiao Li walked 6 kilometers, Xiao Ming started from school by bike to chase Xiao Li, It took 40 minutes to catch up with Xiaoli and find the speed of Xiaoming

Xiao Li walked home from school, 3 kilometers an hour. When Xiao Li walked 6 kilometers, Xiao Ming started from school by bike to chase Xiao Li, It took 40 minutes to catch up with Xiaoli and find the speed of Xiaoming

2 / 3 hours,
2/3*x=6+2/3*3
The solution is x = 12 km

Xiao Li's family lives on the fifth floor. She has already walked 30 steps when she got to the third floor. How many steps does he have to walk when he gets to the fifth floor

50

Xiao Li is playing on a ladder. If she steps four steps, the last three steps are left. If she steps five steps, the last four steps are left. If she steps six steps, the last five steps are left. Q: how many steps does this ladder have at least

I think of two methods, a minimum common multiple
Additional algorithm: (1) decompose to coprime 4 = 2 * 2 * 15 = 5 * 16 = 2 * 3 * 1, so 2 * 2 * 5 * 3 * 1 = 60, and the number of steps is 60-1 = 59