Soru

Zorluk: OrtaCompound Events and Probability Laws

Two marksmen, Kemi and Chidi, independently shoot at a target once. The probability that Kemi hits the target is 0.70.7, and the probability that Chidi hits the target is 0.60.6. What is the probability that at least one of them hits the target?

Cevap: 0.88

Cevap

The probability that at least one marksman hits the target is 0.88.
Since the two shooting attempts are independent, the probability that both marksmen miss is (10.7)×(10.6)=0.3×0.4=0.12(1 - 0.7) \times (1 - 0.6) = 0.3 \times 0.4 = 0.12. Subtracting this probability from 1 yields 10.12=0.881 - 0.12 = 0.88, which represents the probability that at least one marksman hits the target.

Adım Adım Çözüm

1
Find the probability of each event not occurring (missing the target).
P(Kemi misses)=0.3P(\text{Kemi misses}) = 0.3 and P(Chidi misses)=0.4P(\text{Chidi misses}) = 0.4
The sum of an event's probability and its complement is always 1.
2
Determine the probability of both events failing simultaneously.
P(both miss)=0.3×0.4=0.12P(\text{both miss}) = 0.3 \times 0.4 = 0.12
For independent events AA and BB, P(AB)=P(A)×P(B)P(A' \cap B') = P(A') \times P(B').
3
Use the complement rule to find the probability of at least one success.
P(at least one hits)=10.12=0.88P(\text{at least one hits}) = 1 - 0.12 = 0.88
The event 'at least one hits' is the exact complement of 'neither hits'.

Anahtar Kavram

Compound probability laws for independent events and complement of combined events
Bu soruyu puanla