A 95% success rate is the same as a 5% failure rate. You know the number of failures (that's 103302), but you need to know the total. So let T = the total you need.5% T = 103302
So let's re-arrange this to solve for T:
This is the new total you need that will allow 103302 to be 5%. Subtract your original total from this new total to get the amount by which you need to increase your total (without adding any more failures!) to get up to a 95% sucess rate.
Hope this helps!