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.
I don't know if I'm correct, I'm guessing... 30
The answer is -4.
i hope it helps you!
Let the total no. of 25 p coins be x
50p coins = 2x
Value of 25 p coins ( in rupees) = 0.25*x =0.25x
Value of 50p coins ( in rupees) = 0.5*2x = x
0.25x+x = 25
1.25x =25
x = 25/1.25 = 20
no. if 25p coins = 20
and 50p coins = 2*20 = 40
Answer: 1/3
<u>Divide</u>
30/90÷30/30=1/3
Since we are simplifying fractions we divide the numerator and the denominator by a number the fraction can go into.
We could use 10 then divide by 3. You can also just divide by 30 and get the answer.
Let's try dividing by 10 then 3!
30/90÷10/10=3/9
3/9÷3/3=1/3
As you can see we still get 1/3 when we divide by 3. Even tho you have to divide twice you still get 1/3. That's all that matters.