78×.33=25.74 busses are new
25.74+15=40.74 new busses
78+15=93 total busses
40.74/78=0.5223076923= 52% will be new with the new 15 busses
Answer: 1.303639
Step-by-step explanation:
The t-score for a level of confidence
is given by :_
, where df is the degree of freedom and
is the significance level.
Given : Level of significance : 
Then , significance level : 
Sample size : 
Then , the degree of freedom for t-distribution: 
Using the normal t-distribution table, we have

Thus, the t-score should be used to find the 80% confidence interval for the population mean =1.303639
Answer:
Adults= 110
Children= 340
Step-by-step explanation:
Given data
let adults be x
and children be y
x+y= 450----------1
2x+y=680---------2
from 1
x= 450-y
put this in 2
2(450-y)=680
900-2y=680
900-680=2y
220=2y
y= 220/2
y= 110
x+110= 450
x= 450-110
x=340
Answer:

Step-by-step explanation:
Let's solve this by making an equation.
$9 for the helmet, and $5.25 per hour.
h will stand for hours, C will stand for Amanda's cost.

Now, substitute in what we learned from the problem.

This is an equation you can use to solve for the hours.
You have to complete the square. When you do this you get an equation that looks like this: (x-3)^2 + (y+4)^2 = 4. So your center is (3, -4) and your radius is 2. That looks like B to me!!!