Answer:
(mxt) miles
Step-by-step explanation:
hope that this is helpful.
If this is a system of equations then:
Multiply 5x-y=3 by -2
=> -10x+2y=-6
Now you sum the equations:
10x-10x+7y+2y=-3-6
=> 9y=-9
Then just divide by 9: y=-1
Now to get x, choose one of the equations and use the value we got from y:
5x-(-1)=3 => 5x+1=3 => 5x=3-1
=> 5x=2
=> x=2/5
(x,y)=(2/5, -1)
You want to find
P(1000 < X < 3000)
where X is normally distributed with mean 1751 and standard deviation 421. Transform X to Z, so that it follows the standard normal distribution with mean 0 and standard deviation 1 using the relation
X = 1751 + 421Z ==> Z = (X - 1751)/421
Then
P(1000 < X < 3000) = P((1000 - 1751)/421 < (X - 1751)/421 < (3000 - 1751)/421)
… ≈ P(-1.783 < Z < 2.967)
… ≈ P(Z < 2.967) - P(Z < -1.783)
… ≈ 0.9985 - 0.0373
… ≈ 0.9612
so that approximately 96.1% of the students fall in this income range.
