So we are given the mean and the s.d.. The mean is 100 and the sd is 15 and we are trying the select a random person who has an I.Q. of over 126. So our first step is to use our z-score equation:
z = x - mean/s.d.
where x is our I.Q. we are looking for
So we plug in our numbers and we get:
126-100/15 = 1.73333
Next we look at our z-score table for our P-value and I got 0.9582
Since we are looking for a person who has an I.Q. higher than 126, we do 1 - P. So we get
1 - 0.9582 = 0.0418
Since they are asking for the probability, we multiply our P-value by 100, and we get
0.0418 * 100 = 4.18%
And our answer is
4.18% that a randomly selected person has an I.Q. above 126
Hopes this helps!
Answer:
65
Step-by-step explanation:
I think. hope this hepls
Answer:
1st, 2nd, and last.
Step-by-step explanation:
For the first two common rules can be applied such as 
= ![\frac{\sqrt[n]{a} }{\sqrt[n]{b} }](https://tex.z-dn.net/?f=%5Cfrac%7B%5Csqrt%5Bn%5D%7Ba%7D%20%7D%7B%5Csqrt%5Bn%5D%7Bb%7D%20%7D)
and that ![\sqrt[n]{\frac{a}{b} } = (\frac{a}{b})^{n}](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7B%5Cfrac%7Ba%7D%7Bb%7D%20%7D%20%3D%20%28%5Cfrac%7Ba%7D%7Bb%7D%29%5E%7Bn%7D)
and for the last one this is just simplifying the radical and if you factor it you realize that, 
meaning that you can take the radical off of 5/8 and end up with that final answer
Trains depart after every 4 minutes.
Total time train takes to complete a circuit= 24 minutes
Evan sets off at 8:30 am, so he will be back at 8:54 am.
So time of trains coming in opposite direction:
8: 34 am
8:38 am
8:42 am
8:46 am
and 8:50 am
5 trains coming in opposite directions.
Now the trains started at 8:06 am from the stations are:
8:06 am
8:10 am
8:14 am
8:18 am
8:22 am
and 8:26 am.
So there are 6 trains started the circuit at 8:06 am.
Now total number of trains=6+5=11 trains
Answer: 11 trains will pass on complete circuit.
Answer:
Step-by-step explanation:
It seems this system of equations would be solved easier using the elimination method (the x and y values are lined up).
Multiply everything in the first equation by -2 (we want the 4x to be able to cancel out with a -4x).
Now line up the equations (they are already lined up - convenient) and add them from top to bottom.
The -4x and 4x are opposites, so they cancel out.
Adding 6y and 2y gives you 8y, and adding -12 and 4 gives you -8.
Divide both sides by 8.
Since you have the y-value you can substitute this in to the second (or first equation, it doesn't necessarily matter) equation.
Simplify.
Add 2 to both sides.
Divide both sides by 4.
The final answer is 
.
