A number 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?

5

Step-by-step explanation:

let the number written on the board be x.

1st student's number = x + 23

2nd student's number = x - 1

1st student's number = 7 (that of the 2nd student),

x + 23 = 7 (x - 1)

x + 23 = 7x - 7 (expand)

7x - x = 23 + 7 (bring constant to 1 side)

6x = 30 (simplify)

x = 30 : 6 (:6 on both sides)

x = 5

Thus, the number written on the board is 5.