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Zorluk: KolayCompound Probability

A supply cabinet contains 1010 identical safety helmets, of which 22 are yellow and 88 are white. A construction worker randomly selects a helmet, records its color, returns it to the cabinet, and then randomly selects a second helmet. What is the probability of selecting a yellow helmet both times? Express your answer as a decimal.

Cevap: 0.04

Cevap

0.04
Since the helmet is replaced after the first draw, the two events are independent. The probability of drawing a yellow helmet is 210\frac{2}{10} (or 0.20.2). To find the probability of drawing a yellow helmet twice in a row, multiply the probabilities of the two independent events: 0.2×0.2=0.040.2 \times 0.2 = 0.04.

Adım Adım Çözüm

1
Find the probability of the first event.
210\frac{2}{10} or 0.20.2
There are 22 yellow helmets out of 1010 total.
2
Find the probability of the second event.
210\frac{2}{10} or 0.20.2
Because the helmet was replaced, the total number and the number of yellow helmets remain the same.
3
Calculate the compound probability.
0.040.04
For independent events, multiply the individual probabilities together: 0.2×0.2=0.040.2 \times 0.2 = 0.04.

Anahtar Kavram

The probability of two independent events occurring is the product of their individual probabilities: P(A and B)=P(A)×P(B)P(A \text{ and } B) = P(A) \times P(B).
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