A recent flooding weakened pipes throughout a municipality A

A recent flooding weakened pipes throughout a municipality. An inspector is assigned the task of checking pipes of public facilities. The inspector will carry a portable kit (on rollers), which has enough material to repair up to three minor leaks. Past experience suggests that the chance of finding a minor leak at any of the sites to be inspected is 20%. What is the chance that the inspector will use up the kit on the 7th inspection?

Solution