Name a pair of perpendicular line segments?

Keisha makes a large sandwich for a family picnic she takes 1/2 of them the sandwich to the picnic her family eats 3/8 of the whole sandwich what fraction of the whole sandwich does keisha bring back from the picnic

Aparallel system functions whenever at least one of its components works. consider a parallel system of n components, and suppose each component works independently with probability 0.5. find the conditional probability that component n works given that the system is working

How do i do this activity, is appreciated