1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
anygoal [31]
3 years ago
12

The school band is comprised of middle school students and high school students, but it always has the same maximum capacity. La

st year the ratio of the number of middle school students to the number of high school students was 1:8. However, this year the ratio of the number of middle school students to the number of high school students changed to 2:7. If there are 18 middle school students in the band this year, how many fewer high school students are in the band this year compared to last year?
Mathematics
1 answer:
alexandr1967 [171]3 years ago
6 0
> Last year the ratio of the number of middle school students
> to the number of high school students was 1:8.
1/9 x + 8/9 x = makeup of middle and high school students

> this year the ratio ... changed to 2:7
2/9 x + 7/9 x = x (again)

> there are 18 middle school students in the band this year
2/9 x = 18
2x = 9 * 18 → x = 81

Total = 81 in band ...
Last year:
1/9 and 8/9 = 9 and 72
This year
2/9 and 7/9 = 18 and 63

And from there you can figure out the changes:
+9 for middle school (which is increase from 1/9 to 2/9)
--9 for high school (which is decrease from 8/9 to 7/9)
You might be interested in
For what value of x will 55 and x have the mean (average) as 67
AlekseyPX
If (55 + x)/2 is to be 67, then 55+x = 2*67, so x = 2*67 - 55 = 79
4 0
3 years ago
Read 2 more answers
What is this expression in simplest form?
gayaneshka [121]

Answer:

A. 1÷(X+1) (x-2)

some steps are directly

tag me in brainlist if you like it

8 0
2 years ago
Use the Fundamental Theorem for Line Integrals to find Z C y cos(xy)dx + (x cos(xy) − zeyz)dy − yeyzdz, where C is the curve giv
Harrizon [31]

Answer:

The Line integral is π/2.

Step-by-step explanation:

We have to find a funtion f such that its gradient is (ycos(xy), x(cos(xy)-ze^(yz), -ye^(yz)). In other words:

f_x = ycos(xy)

f_y = xcos(xy) - ze^{yz}

f_z = -ye^{yz}

we can find the value of f using integration over each separate, variable. For example, if we integrate ycos(x,y) over the x variable (assuming y and z as constants), we should obtain any function like f plus a function h(y,z). We will use the substitution method. We call u(x) = xy. The derivate of u (in respect to x) is y, hence

\int{ycos(xy)} \, dx = \int cos(u) \, du = sen(u) + C = sen(xy) + C(y,z)  

(Remember that c is treated like a constant just for the x-variable).

This means that f(x,y,z) = sen(x,y)+C(y,z). The derivate of f respect to the y-variable is xcos(xy) + d/dy (C(y,z)) = xcos(x,y) - ye^{yz}. Then, the derivate of C respect to y is -ze^{yz}. To obtain C, we can integrate that expression over the y-variable using again the substitution method, this time calling u(y) = yz, and du = zdy.

\int {-ye^{yz}} \, dy = \int {-e^{u} \, dy} = -e^u +K = -e^{yz} + K(z)

Where, again, the constant of integration depends on Z.

As a result,

f(x,y,z) = cos(xy) - e^{yz} + K(z)

if we derivate f over z, we obtain

f_z(x,y,z) = -ye^{yz} + d/dz K(z)

That should be equal to -ye^(yz), hence the derivate of K(z) is 0 and, as a consecuence, K can be any constant. We can take K = 0. We obtain, therefore, that f(x,y,z) = cos(xy) - e^(yz)

The endpoints of the curve are r(0) = (0,0,1) and r(1) = (1,π/2,0). FOr the Fundamental Theorem for Line integrals, the integral of the gradient of f over C is f(c(1)) - f(c(0)) = f((0,0,1)) - f((1,π/2,0)) = (cos(0)-0e^(0))-(cos(π/2)-π/2e⁰) = 0-(-π/2) = π/2.

3 0
4 years ago
PLEASE HELP!!!
just olya [345]

Answer:

-3(1.5n - 1)

your welcome

3 0
3 years ago
Read 2 more answers
What is 8 thousandths less than 4.989?
emmainna [20.7K]
8000-4.989 so when you see the word less than it means that you have to subtract and more than you have to add so the answer for this question will be 7,995.011
8 0
3 years ago
Other questions:
  • State the property that justifies the statement
    15·1 answer
  • Find the average rate of change for f(x)=x+6 over the interval [4,8]
    15·2 answers
  • Can someone help me drag this please correct answers only
    15·2 answers
  • I dont know how to do this one :(((
    7·1 answer
  • Help please asp. !!!
    13·1 answer
  • Jenna is at a fair with four friends. They all want to ride the roller coaster, but only three people can fit in a car. How many
    11·1 answer
  • PLEASE THIS IS TIMED what is the slope of the line shown ? <br>( its a number answer) ​
    6·2 answers
  • Pls help me as fast as possible
    6·2 answers
  • (5x)^3It’s asking me to evaluate pls help
    8·1 answer
  • What is the median of the data set 11,13,15,21,23,31,31,33?<br> A. 31<br> B. 21<br> OC. 23<br> D. 22
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!