There is an Olympic math problem, I don't know how to do it: two brothers ride into the city, the whole journey is 5 1 thousand miles, but only one person can ride it. Brother travels 5 thousand miles an hour, brother We can arrive at the city at 65438+ 0: 45 pm at the same time.

Solution: Suppose my brother walks X kilometers, and the equation is:

X/5+(5 1-X)/ 12 =(5 1-X)/4+X/ 12

X/5+5 1/ 12-X/ 12 = 5 1/4-X/4+X/ 12

17/60X=5 1/6

X=30

30/5+(51-30)/12 = 6+7/4 = 7 and 3/4 (hours) = 7 hours and 45 minutes.

Depart at 6: 00 a.m. and arrive at 1: 45 p.m. in 7 hours and 45 minutes.

A: We can get to the city at 1: 45 in the afternoon.

analyse

Suppose my brother walked x kilometers and he rode 5 1-X kilometers, while my brother walked 5 1-X kilometers and rode x kilometers. According to the meaning of the question, he got x/5+(51-x)/12 = (5/kloc)

The key to this problem is to find the exact equivalence relation and solve it according to the time equality equation used by the two men.

Extended data:

Steps to solve application problems with column equations

1, practical problems (review, find out all known and unknown conditions and quantitative relationships).

2. Set the last known number, and use the algebraic expression of the set last known number to represent all the last known quantities.

3. Find the equation relationship.

4. Solve the equation and find other unknowns.

5, test (test whether it is the solution of the original equation, whether it is in line with the practical significance).

6. answer.