9) 4/50 = 0.08 = 8%
10) 65 * 0.20 = 13
13 vehicles
Answer:
Teacher's age is 32.
Step-by-step explanation:
How you count the average age for people is:
(age of person 1 + age of person 2 ... ) / number of people = average age
Let's start by observing that we've got 2 equations coming from the text:
- average of just students
20 students x 11 (average for a student) = sum of age of students
20 x 11 = 220 - average of student and teacher
let's say x is age of teacher
together students & teacher is 20 + 1 = 21 people
(20 students x 11 + x)/ (20 + 1) = 12
(220 + x) / 21 = 12
220 + x = 12 * 21
x = 12 *21 - 220
x = 252 - 220
x = 32
hope this helps ❣️
So hmmm x²+6x+8=0
alrite.. let's do some grouping now
( x² + 6x + [?]²) + 8 = 0
notice above, we have a missing fellow in order to get a perfect square trinomial... hmm who would that be?
let's take a peek at the middle guy of the trinomial.. 6x.. hmmm let's factor it, 2*3*x, wait a minute! 2 * 3 * x... we already have x² on the left-side, since the middle term is just 2 * the square root of the other two terms, that means that the guy on the right, our missing guy must be "3"
alrite, let's add 3² then, however, bear in mind that, all we're doing is borrowing from our very good friend Mr Zero, 0
so if we add 3², we also have to subtract 3², let's do so
(x² + 6x +3² - 3²) + 8 = 0
(x² + 6x +3²) + 8 - 3² = 0
(x+3)²=3² - 8
(x+3)² = 1
Answer:
The model is 
.
Step-by-step explanation:
Consider the given information.
The volume of air inside the lungs increases or decreases so for this we will use the basic sine function ![B(t)=d+a\sin[b(t+ \frac{c}{a})]](https://tex.z-dn.net/?f=B%28t%29%3Dd%2Ba%5Csin%5Bb%28t%2B%20%5Cfrac%7Bc%7D%7Ba%7D%29%5D)
as our parent function.
Let us assume that the phase shift is 0 it means 
.
The air that moves into and out of the lungs is about 498 mL.
It means the amplitude of the function will vary by 249(half of 498).
The reserve and residual volumes of air that remains in the lungs occupy about 1990 mL which is the minimum air in the lungs.
So, the max air will be: 1990+498 =2488 mL
And the average will be d=1990+249=2239 ml
The horizontal stretch will be 
as we know that period of 
is 
and respiratory cycle for an average human takes about 4 seconds.
Hence, the model is .
The answer is one solution
