When 18 is added to 6 times a certain number the result is 168. What is the number?

Let's represent the unknown number as x. The equation for this problem can be written as 6x + 18 = 168. To solve for x, we first subtract 18 from both sides to isolate the term with x, giving us 6x = 150. Finally, we divide both sides by 6 to find that the number is x = 25.