Write a letter to the editor of a local newspaper expressing your concerns about the increasing “Pollution levels in your city”. You are an environmentalist, Radha/Rakesh, 46, Peak Colony, Haranagar. You may use the following cues along with your own ideas: 
Four students of class XII are given a problem to solve independently. Their respective chances of solving the problem are: \[ \frac{1}{2},\quad \frac{1}{3},\quad \frac{2}{3},\quad \frac{1}{5} \] Find the probability that at most one of them will solve the problem.