Answer:
330
Step-by-step explanation:
This is the "choose" formula.
The equation for the choose formula is this:
nCk = n! / k!(n-k)!
! = factorial.
Plug in our numbers:
11C4 = 11! / 4!(11-4)!
39916800 / 24(5040)
39916800 / 120960
330
The number of days in which the air quality index exceed 100 in the year 1988 is 75 days. Then the correct option is B.
<h3>What is a function?</h3>
The function is an expression, rule, or law that defines the relationship between one variable to another variable. Functions are ubiquitous in mathematics and are essential for formulating physical relationships.
The air quality index (AQI) is given by the function.
Where n be the number of days the AQI exceeds 100 in a given year.
For 
, then we have
More about the function link is given below.
brainly.com/question/5245372
Okay so for substitution, chose one of of the equations to solve for x. Let's solve for the second one. So you have 2x-8y=32.
Start by adding 8y to both sides:
2x=8y+32.
Then you have to get x by itself so you divide both sides by 2 which will give you:
x=4y+16.
Now you have:
6x-4y=36
x=4y+16 (this was 2x-8y=32)
Now, plug in the second equation to the first one. You would do so by plugging in the second equation to where you see x. You would have:
6(4y+16)-4y=36
Now, multiply the 6 with the 4y and 16. you would then have:
24y+96-4y=36.
Now, combine your like terms to get:
20y+96=36
Then subtract 96 to both sides:
20y=-60
Then divide both sides so that you have y all by itself:
y=-30!
You now have the answer for y, so now plug what you got for y into the other equation: x+4y=16:
x+4(-30)=60
Solve for x:
x-120=60
add 120 to both sides:
x=180!
so Your answer is Y=-30 and X=180
I hope this helped:)
