I'm having difficulty to understand this question. Can I know what formula do I need to use in order to solve this? I'm already know the answer but I can't find any related formula that can be used to calculate the questions. If not troubling you, can you explain more details about how to solve this? In the future, I can easily identify this type of question and won't repeat the same mistake. thank you.

For this, I include the answer for the following questions. (a) 0.62 (b) 0.24 (c) 0.31

A flow measurement system consists of an orifice plate (1 = 0.75), differential pressure transmitter (1 = 1.0), square root extractor (2 = 0.1) and recorder (1 = 0.1). Calculate the probability of losing the flow measurement after 0.5 year for the following: (a) A single flow measurement system (b) Three identical flow measurement systems in parallel (c) A system with three orifice plates, three differential pressure transmitters and a middle value selector relay (1 = 0.1). The selected transmitter output is passed to a single square root extractor and recorder. Annual failure rate data are given in brackets; assume that all systems were initially checked and found to be working correctly