The block of a seismic station consists of three subblocks. The first subblock consist of n 1 elements, the second one consists of n 2 elements, the third one consist of n 3 elements. The first...

The block of a seismic station consists of three subblocks. The first subblock consist of n₁
elements, the second one consists of n₂
elements, the third one consist of n₃
elements. The first subblock is unconditionally necessary for the operation, second and third duplicate each other. The failure flow is a stationary one; for the elements which are included in the first subblock, the intensity of the failure flow is equal λ₁, in the second or third subblocks the intensity of the failure flow is equal λ₂. The first subblock fails, if not less than two elements fail. The second (third) subblock fails if even of one element fails. The block of the seismic station fails if the first subblock or second and third subblocks fail together. To find the probability that during a time τ the block of the seismic station will leave out of the operation.

The artificial satellite revolving during n of day, may collide randomly with meteorites. The meteorites are traversing an orbit and colliding with the satellite, form a stationary Poisson flow with intensity κ (meteorites per day). The meteorite which has hitted the satellite, punches its envelope with the probability p0. The meteorite, which has punched an envelope, puts out of the action the devices of the satellite with probability p1. To find the probability of the following events:

(A) — {the envelop is punched during flight time};

(B) — {the devices put out of action during flight time};

(C) — {the envelop is punched but the devices do not put out of the action during the flight time}.