Question

A manufacturer uses electrical fuses in an electronic system. The fuses are purchased in large lots and tested sequentially until the first defective is observed. If the lot contains 10% defective fuses, find the probability that 5 fuses are tested before a defective fuse is observed.

Answer 1

Solution :

Let G denote a good (non-defective) fuse and let D denote a defective fuse.

P(G)= 0.9

P(D)= 0.1

The probability desired is P(GGGGD) =

(0.9) (0.9)(0.9)(0.9)(0.1) =

0.06561.