7x, 4y, 1are the terms, and 7x is the leading term.
Answer: The probability that exactly 2 insects will survive = 0.2501
Step-by-step explanation:
Given: A certain insecticide kills 80% of all insects in laboratory experiments.
The probability that a particular insect survives= 1-0.80=0.20
Sample size: n=14
Binomial probability distribution:
, where x= number of successes , p=probability of success in each trial, n= sample size.
The probability that exactly 2 insects will survive = 

Hence, the probability that exactly 2 insects will survive = 0.2501
Answer:
b = 4
r = 3
Step-by-step explanation:
r + b = 7
solve for 'r' to get r = 7-b
now substitute '7-b' for r in the second equation:
3.75(7-b) + 2.75b = 22.25
26.25 - 3.75b + 2.75b = 22.25
-b = -4
b = 4
r = 3
Using the z-distribution, it is found that the smallest sample size required is given by:
B) 7 vehicles.
<h3>What is the margin of error for a z-distribution confidence interval?</h3>
It is given by:

In which:
is the population standard deviation.
In this problem, we have a 90% confidence level, hence
, z is the value of Z that has a p-value of
, so the critical value is z = 1.645.
The margin of error and the population standard deviation are given by, respectively:
.
Then, we solve for n to find the needed sample size.






Rounding up, 7 vehicles have to be sampled, hence option B is correct.
More can be learned about the z-distribution at brainly.com/question/25890103
It would be the third. X+3=y