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Zorluk: OrtaCompound Events and Probability Laws

In an electrical power station, two independent backup transformers, T1T_1 and T2T_2, operate simultaneously during power surges. The probability that T1T_1 fails during a surge is 0.150.15, and the probability that T2T_2 fails during the same surge is 0.200.20. What is the probability that at least one transformer functions correctly during a power surge?

Cevap: 0.97

Cevap

0.97
The failure probabilities are P(F1)=0.15P(F_1) = 0.15 and P(F2)=0.20P(F_2) = 0.20. By the multiplication law for independent events, the probability of both failing is P(F1F2)=0.15×0.20=0.03P(F_1 \cap F_2) = 0.15 \times 0.20 = 0.03. Using the complement rule, the probability of at least one functioning correctly is 1P(F1F2)=10.03=0.971 - P(F_1 \cap F_2) = 1 - 0.03 = 0.97.

Adım Adım Çözüm

1
Determine the joint probability of both transformers failing.
P(F1F2)=0.15×0.20=0.03P(F_1 \cap F_2) = 0.15 \times 0.20 = 0.03
Since the operational failures of the two transformers are independent events, the probability of both failing together is the product of their individual failure probabilities.
2
Calculate the probability that at least one transformer functions correctly.
P(at least one functions)=10.03=0.97P(\text{at least one functions}) = 1 - 0.03 = 0.97
The event that at least one transformer functions is the complement of the event that both transformers fail simultaneously.

Anahtar Kavram

Independent Compound Events and the Complement Rule
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