Fast Fractions

Ishita has been given tons of homework from the HOD of C.S.E department, and she is depressed as it's too much for her to solve alone. She asks for your help to help her get done with her work. You are given two integers, $P$ and $Q$ where $P$ $is$ $less$ $than$ $Q$, and a single digit R. Your task is to find the first location of the digit $R$ in the decimal representation of P/Q ( P divide