Final answer:
Without specific information about the hydraulic system's design and condition, it's impossible to determine the exact number of brake applications the brake accumulators can provide after a hydraulic pressure loss.
Step-by-step explanation:
The question pertains to the number of brake applications provided by the brake accumulators after a loss of hydraulic system 2 or 3 pressure. Although the exact number can vary depending on the design and condition of the aircraft or vehicle system, typically, brake accumulators are designed to provide pressure for a limited number of brake applications. Each application uses some of the stored pressure until the accumulator is depleted. However, the question does not provide enough information to determine a specific number of applications for a given system. Therefore, without knowing the specifications of the hydraulic system in question, one cannot accurately state whether it is 6, 20, 25, or 30 applications. In general, this involves principles such as Pascal's Principle and the operation of hydraulic systems, where pressure exerted at one point is transmitted to other points within the fluid.