Question

15. The sum of 25 consecutive numbers is 900. Find the second largest number.

 

Answer 1

Dịch ra là: Tổng của 25 số liên tiếp là 900. Tìm số lớn thứ hai.
 

Answer 2

T.khảo!

The average of the integers must be 20. And since they are consecutive, the one in the middle of the 45 must be equal to the average. That means the 23rd of your 45 numbers is equal to 20. So the 22nd is 19, the 21st is 18, and so on. Notice that the value of the integer is always 3 less than which place it is in the sequence. So the 1st integer must be -2.

Answer 3

Set the smallest number is a

So the largest number is a+25

\(\Rightarrow\dfrac{\left(a+25+a\right)\cdot25}{2}=90\\ \Rightarrow\left(2a+25\right)\cdot25=180\\ \Rightarrow2a+25=7,2\\ \Rightarrow a=-8,9\)

So the second largest number is \(-8,9+25-1=15,1\)

Answer 4

theo gg dịch thì :  Tổng của 25 số liên tiếp là 900. Tìm số lớn thứ hai.