Anumber was written on the board. one student increased the number by 23, but another student decreased the number by 1. the first student's result was 7 times greater than the result of the second student. what is the number written on the board?

Let the number be x.

First student increased the number by 23, therefore
⇒ x + 23

Second student decreased the number by 1, therefore
⇒ x - 1

The first student's result was 7 times greater than the result of the second student's, therefore
⇒ x + 23 = 7(x - 1)


Solve for x:

x + 23 = 7( x- 1)
x + 23 = 7x - 7
6x = 30
x = 5


The  number on the board is 5.

The first one is correct