The original fraction has a denominator that is 3 less than the numerator. If we define the numerator as x, then the denominator is x-3, and the fraction can be written as x/(x-3).
If 1 is added both to the numerator and denominator, the resulting fraction is equal to 10/7.
Then, we can write:

With the value of x, we can replace it in the fraction and know the value of it:

Answer: The fraction is 9/6, that can be simplified to 3/2 or 1.5.