A rides a bicycle. B rides a motorcycle from two places 72 kilometers apart. After three hours of meeting, it is known that B's speed is three times that of A Q: how many kilometers did they walk when they met?

A rides a bicycle. B rides a motorcycle from two places 72 kilometers apart. After three hours of meeting, it is known that B's speed is three times that of A Q: how many kilometers did they walk when they met?

A = 72 △ 1 + 3 = 18 km
B = 72-18 = 54 km

The sum of 25 continuous natural numbers is 2000. What is the largest even number?
It's before 7:00 today

Let the first number be n, then the second number is n + 1, and so on, the 25th number is n + 24
n+(n+1)+(n+2)...+(n+24)=2000
25n+300=2000
n=68
The 25th is even
So the largest even number is 92

The sum of 25 consecutive even numbers is 2000. What is the largest even number
Why?

The maximum number is 104. You assume that the smallest even number is x, followed by (x + 2), (x + 4) (x + 48), this is an arithmetic sequence. After calculating with the arithmetic sequence formula (you should know the specific calculation steps), you can get x = 56, then the maximum number is 56 plus 48, and you can get 104,

Given a column number 1, - 2,3, - 4,5, - 6... Arrange the column number in the following form: first line 1, second line - 2,3
What is the fourth number in the seventh line

Number rule: odd number is positive, even number is negative. Arrangement rule: row n numbers in the nth row
The first six rows are 1 + 2 + 3 + 4 + 5 + 6 = 21, 21 + 4 = 25
25 is odd and positive, and the fourth number in line 7 is 25