Can you please solve this problem.

A production line manager, J, is trying to design a manufacturing line, using the machines that her company already has. Based on the historical records, each individual candidate machine will fail, during the production, with a probability of 1-p, and their failures are independent. Since the company plans to discard the machines after the production, J has no budget to repair any failure machine. The line is considered as working properly if at least 50% of the machine(s) in the line remain operative, otherwise the production is considered failed. There are two options for line design:

a. Using four machines;

b. Using two machines.