Need with my fractions i’m stuck on number 2.

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

The graph shows the amount of money noah earned based on the number of lawns he cut. which list shows the dependent quantities in the graph?

Arace is 10 kilometers long. markers will be placed at the beginning and end of the race course and at each 500 meter mark. how many markers are needed to mark the course for the race?