Use this formula.
and solution is:［（18！）/（6！×（18-6）！）］×（1/2）^6×（1-1/2）^（18-6）≈0.0781604
7.8%
The perimeter of a triangle is the sum of its side lengths.
The perimeter of the triangle is: 
<u>The sides of the triangle are:</u>
Side 1 = (8d - 3) cm
Side 2 = (6d + 2) cm
Side 3 = (7f + 8) cm
The perimeter (P) is calculated as:
P = Side 1 + Side 2 + Side 3
So, we have:
Remove brackets
Collect like terms
Hence, the perimeter of the triangle is:
Read more about perimeters at:
brainly.com/question/6465134
(a) Average time to get to school
Average time (minutes) = Summation of the two means = mean time to walk to bus stop + mean time for the bust to get to school = 8+20 = 28 minutes
(b) Standard deviation of the whole trip to school
Standard deviation for the whole trip = Sqrt (Summation of variances)
Variance = Standard deviation ^2
Therefore,
Standard deviation for the whole trip = Sqrt (2^2+4^2) = Sqrt (20) = 4.47 minutes
(c) Probability that it will take more than 30 minutes to get to school
P(x>30) = 1-P(x=30)
Z(x=30) = (mean-30)/SD = (28-30)/4.47 ≈ -0.45
Now, P(x=30) = P(Z=-0.45) = 0.3264
Therefore,
P(X>30) = 1-P(X=30) = 1-0.3264 = 0.6736 = 67.36%
With actual average time to walk to the bus stop being 10 minutes;
(d) Average time to get to school
Actual average time to get to school = 10+20 = 30 minutes
(e) Standard deviation to get to school
Actual standard deviation = Previous standard deviation = 4.47 minutes. This is due to the fact that there are no changes with individual standard deviations.
(f) Probability that it will take more than 30 minutes to get to school
Z(x=30) = (mean - 30)/Sd = (30-30)/4.47 = 0/4.47 = 0
From Z table, P(x=30) = 0.5
And therefore, P(x>30) = 1- P(X=30) = 1- P(Z=0.0) = 1-0.5 = 0.5 = 50%
Answer:
The second one.
Step-by-step explanation:
The pattern is red with 0 arrows, blue with 1 arrow, red with 2 arrows, so it would be blue with 3 arrows.
