If Party A and Party B want to reach the finish line at the same time, when Party B runs100× 5/4 =125m.
Therefore, the starting line of A is backward 125- 100 = 25m.
The comprehensive formula is:100× [100 ÷ (100-20)}-100 = 25.
2. A number divisible by 1 1, characterized in that the difference between the sum of odd digits and the sum of even digits of the number is 0 or a multiple of 1 1.
From 1 to 9, the total is 45. If the difference between the sum of two groups is 0 or multiple of 1 1, it should be (45-1) ÷ 2 =17,45-17.
The sum of four digits is 17, and the sum of five digits is 28.
In order to minimize the number, the first four digits of 9 digits must be 1234.
So a set of 4 digits contains 2 and 4, and the rest are 5 and 6.
A set of 4 digits contains 1 and 3, and the rest are 7, 8 and 9.
The number is 123475869.