Rating equation that has a rate of change (slope) greater than one function, but less the rate of change (slope) The other function. Can someone help me please?

Successful implementation of a new system is based on three independent modules. module 1 works properly with probability 0.96. for modules 2 and 3, these probabilities equal 0.95 and 0.90. compute the probability that at least one of these three modules fails to work properly.

Solve this problem! extra ! 3025/5.5 = a/90.75

Simplify using positive exponents only.