We are given that 18 is added to a number. If the number is "n", then we can write this mathematically as:

We are also given that the result is divided by 6. This is written as:

Now, we are given that the result is equal to 1/4 of the number plus 1, this is written as:

Now, to determine the number we will solve for "n". First, we will distribute the denominator of the fraction on the left:

Now, we subtract n/4 from both sides:

Solving the operations:

Now, we simplify the fraction on the left side:

Now, we subtract 3 from both sides:

Solving the operations:

Now, we multiply both sides by -12:

Therefore, the number is 24.