An urn contains \(19\) red balls and \(9\) blue balls. Find the minimum number of blue balls that must be added so that the probability of drawing a blue ball is greater than \(0.65\).
An urn contains \(12\) red balls and \(30\) blue balls. Find the minimum number of red balls that must be added so that the probability of drawing a red ball is greater than \(0.66\).
The pictures show parts of graphs of functions that are decreasing on the interval \([1;5]\). Choose the picture showing the part of the graph of the function \(f(x)=\frac{x+7}{x+1}\).