What's the least common denominator of 4 and 16

Can i get some on 18,20,& 22? or one of them

Find the length of cu, the triangles are similar.

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.