Answer:
The number is 9.
Solution:
Let the number be x.
In the question it is given that when 15 is reduced from one-third of a number the result is 12. Since we have assumed the number to be x, therefore one - third of a number is given by 1/3x.
Using the below equation we will try to find the value of x.

Grouping the terms,


Therefore,

x=9
Thus, the number is 9.