A company has a security system comprising four electronic devices (A, B, C, and D) which operate independently. Each device has a probability of failure of 0.1. The four electronic devices are arrang

A company has a security system comprising four electronic devices (A, B, C, and D) which operate independently. Each device has a probability of failure of 0.1. The four electronic devices are arranged so that the whole system operates properly if at least one of A or B functions and at least one of C or D functions. What is the probability that the whole system functions properly?