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1 answer:
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Answer:
Step-by-step explanation:
If k items out of 20 total items are defective, then the number of non-defective item is 20 – k. The probability of choosing 5 items where all of them are non-defective is
- For the 1st slot the chance is (20 – k)/20
- For the 2nd slot the chance is (20-k-1)/(20-1) = (19-k)/19
- For the 3rd slot: (18 – k)/18
- 4th : (17 – k)/17
- 5th: (16 – k)/16
The probability in total would be
So the probability of selecting at least 1 defective item is the inverse of this, which is
Answer:
It takes takes them 31.67 secs to meet after Person A starts walking
OR
34.67 secs after Person B starts walking
Step-by-step explanation:
First, we will find the perimeter of the rectangle
From,
Perimeter of rectangle = 2 ( +
)
Where is the length
and is the breadth
From the question, = 100m
and = 50m
Hence,
Perimeter of the rectangle = 2 (100+50)
= 2(150) = 300m
Hence, the perimeter of the rectangle is 300m
This is the total distance that will be covered by both persons by the time they meet.
Let the distance covered by person A be
and the distance covered by person B be
We can write that
+
= 300m
Velocity of person A, = 4 m/s
and velocity of person B, = 5 m/s
From the question, Person A starts walking 3 seconds after person B,
This means, if person A spends secs before they meet, then person B would spend (3 +
) secs.
For Person A,
Velocity = 4 m/s
Time = secs
Distance =
From,
Then,
...... (1)
For Person B
Velocity = 5 m/s
Time = (t + 3) secs
Distance =
Also, from
...... (2)
Recall that, +
= 300m
Then, = 300m -
We can then write that,
300m -
Then,
..... (3)
Equating equations (1) and (3), we get
This is the time spent by Person A
Hence, it takes takes them 31.67 secs to meet after Person A starts walking OR
34.67 secs after Person B starts walking