Answer:
23
Step-by-step explanation:
Since 2/10 = 4/20, we know that a-3 = 20, so a = 20 + 3 = 23.
Answer:
0.3108 is the probability that the sample mean is between 7.8 and 8.2 minutes.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 8 minutes
Standard Deviation, σ = 2.5 minutes
Sample size, n = 25
We are given that the distribution of time spent is a bell shaped distribution that is a normal distribution.
Formula:

Standard error due to sampling =

P(sample mean is between 7.8 and 8.2 minutes)

0.3108 is the probability that the sample mean is between 7.8 and 8.2 minutes.
Answer:
52.48
Step-by-step explanation:
find the cross sectional area which is the triangle
triangle = 1/2 x 8.2 x 6.4 = 26.24
then, use the area to multiply by the extended length of 2
26.24 x 2 = 52.48
I hope this helps you
11-5i
Answer:
17
Step-by-step explanation:
11 + 17 = 28
17 - 6 = 11