Answer:
The fraction of horses that are Morgan's=17/20
Step-by-step explanation:
Step 1: Determine fraction for each breed
Arabians=1/4
Thoroughbreds=2/5
Morgan's=unknown
Step 2: Express each breed as a fraction of the total
Number of Arabians=fraction of Arabians×total number of horses
Let total number of horses be x
Arabians=(1/4)×x=1/4 x
Thoroughbreds=(2/5)×x=2/5 x
Morgans's=m
Step 3: Calculate fraction of Morgans
Total number of horses=Arabians+Thoroughbreds+Morgans
x=(1/4)x+(2/5)x+m
solve for m;
m=x-(1/4)x-(2/5)x
m=x-3/20x
m=17/20 x
The fraction of horses that are Morgan's=17/20
First one is 72/100 or 1/3
Answer:
0.0039 is the probability that the sample mean hardness for a random sample of 12 pins is at least 51.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = 50
Standard Deviation, σ = 1.3
Sample size, n = 12
We are given that the distribution of hardness of pins is a bell shaped distribution that is a normal distribution.
Formula:
Standard error due to sampling =

P(sample mean hardness for a random sample of 12 pins is at least 51)
Calculation the value from standard normal z table, we have,
0.0039 is the probability that the sample mean hardness for a random sample of 12 pins is at least 51.