Let us assume a period of two years.
But then that mean that the person has actually gained Rs. 95 in two years.
Now if every citizen commits a fraud of Rs. 100 then he will gain Rs. 95 ultimately in two years and that would mean that the country as a whole is gaining something from corruption and not losing anything?
There's definitely something missing in this hypothesis.
You missed something. In case of tax evasion, the person isn't gaining Rs 95, he's saving Rs 95. There's a huge difference.
In case of corruption, the person who gained Rs 95, has removed those Rs 95 from the Tax system of the country. Now those Rs 95 would be unaccounted for in records. So the country has lost Rs 95 there, whereas the person has gained Rs 95.
So actually the money doesn't go anywhere, it just becomes useless as it can not be used for the development of the country. When the corruption is increases, huge amounts of money start escaping the tax system. So the state starts running short of money, which stagnates growth, development, which results in problems like price rise, loss of jobs and inefficiency. So in the end it hurts the person who was corrupt. He may be driving a Mercedes, but he won't get the smooth roads to drive on. The money he spent on the Merc will be taken away by the Germans. He will be rich, but in the process thousands of other people will become poor.
Also, since the govt is running short on money, it takes loans from other countries, needs to spend more on development, and ends up broke.
This is a very brief way in which money from corruption is lost, and the country gets poorer.