Answer:
7.5 miles per hour
Step-by-step explanation:
Average speed over the interval [1, 3] = (distance at 3 hrs -distance at 1 hr)/(3 hrs - 1 hr)
From the graph:
Distance at 3 hrs = 30 => (3, 30)
Distance at 1 hr = 15 => (1, 15)
Average speed = (30 - 15)/(3 - 1)
Average speed = 15/2
= 7.5
Therefore, average speed = 7.5 miles per hour
A+c=100
3a+2c=275, from the first c=100-a making the 2nd equation become:
3a+2(100-a)=275 perform indicated multiplication on left side
3a+200-2a=275 combine like terms on left side
a+200=275, subtract 200 from both sides
a=75, and since c=100-a
c=100=75=25
So the answer is D. 25 children and 75 adults
Equation 1: a+c=100
Equation 2: 3a+2c=275
Answer: A. Mean of sampling means 
Standard deviation of sampling means =
B. The probability that your sample has mean less than 165 is 0.1492 .
Given : The distribution of blood cholesterol level in the
population of young men aged 20 to 34 years is close to normal with
mean
Mg/dl and standard deviation
mg/dl.
Sample size : n= 150
Let
sample mean values.
A. The mean and the standard deviation of the distribution of the sampling means would be :
Mean of sampling means =
Standard deviation of sampling means = 

The probability that your sample has mean less than 165 would be

Hence , the probability that your sample has mean less than 165 is 0.1492 .