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
kodGreya [7K]
3 years ago
7

a man used $3 to pay for 16 postage stamps. x of them are 15 cents each and the rest are 20 cents each. a) Write down an equatio

n in terms of x and find the value of x. b) is the man supposed to receive and change? If so, find the amount
Mathematics
1 answer:
Vaselesa [24]3 years ago
7 0

Answer:

Step-by-step explanation:

x = 15 cent stamps

y = 20 cent stamps

I will be using these equations

x + y = 16

0.15x + 0.20y = 3

x = 16 - y

0.15(16 - y) + 0.20y = 3

2.40 - 0.15y + 0.20y = 3

-0.15y + 0.20y = 3 - 2.40

0.05y = 0.60

y = 0.60/0.05

y = 12.......there were 12 twenty cent stamps

x + y = 16

x + 12 = 16

x = 16 - 12

x = 4.....there were 4 fifteen cent stamps

no change is received

You might be interested in
Solve the equation for principal values of x. Express solutions in degrees.
Hitman42 [59]

Option C:

x = 90°

Solution:

Given equation:

\sin x=1+\cos ^{2} x

<u>To find the degree:</u>

\sin x=1+\cos ^{2} x

Subtract 1 + cos²x from both sides.

\sin x-1-\cos ^{2} x=0

Using the trigonometric identity:\cos ^{2}(x)=1-\sin ^{2}(x)

\sin x-1-\left(1-\sin ^{2}x\right)=0

\sin x-1-1+\sin ^{2}x=0

\sin x-2+\sin ^{2}x=0

\sin ^{2}x+\sin x-2=0

Let sin x = u

u^2+u-2=0

Factor the quadratic equation.

(u+2)(u-1)=0

u + 2 = 0,  u – 1 = 0

u = –2, u = 1

That is sin x = –2, sin x = 1

sin x can't be smaller than –1 for real solutions. So ignore sin x = –2.

sin x = 1

The value of sin is 1 for 90°.

x = 90°.

Option C is the correct answer.

3 0
2 years ago
Read 2 more answers
The equation y = 1/4x represents a proportional relationship. What is the constant of proportionality?
Andrew [12]

Answer:

[see below]

Step-by-step explanation:

The equation is in the form:

y = kx

Where k is the constant of proportionality.

Since 1/4 is in k's spot, the constant of proportionality should be '1/4'.

Hope this helps.

4 0
2 years ago
I need help ASAP help me answer questions and then I put a picture up
olya-2409 [2.1K]

Answer:

(-4,9)

Step-by-step explanation:

To solve the system of equations, you want to be able to cancel out one of the variables. In this case, it'd be easiest to cancel out the x variables. To do this, you'll want to multiply everything in the first equation by 2 (2(x-5y=-49)=2x-10y=-98). Then, you can add the two equations together. 2x and -2x will cancel out, so you'll be left with -11y=-99. Next, solve for x by dividing both sides of the equation by -11, which will give you y=9. This is your y-coordinate! At this point, you're halfway to the answer as you just need your x-coordinate. It's not too difficult to find the x-coordinate, since you just substitute 9 into one of the equations. It doesn't matter which one you choose as you should get the same answer with both. I usually substitute the y-value into both equations, though, just to make sure I'm correct. Once you put the y-value into the equations, you should get x=-4 after solving it. :)

5 0
3 years ago
This is a test i'm taking there's 8 questions. This is due today it would be great if I got help on all the questions
MA_775_DIABLO [31]

Answer:

DEF

Step-by-step explanation:

The other triangle is a reflection

8 0
3 years ago
A student attempted to generate an equivalent expression using the distributive property, as shown below:
Schach [20]
It is 6 was not multiplied by 3
The answer should be 6(m+3)= 6m+ 18
5 0
3 years ago
Read 2 more answers
Other questions:
  • Find each mass in kg a)The mass of a male giraffe is about 1.9 t.
    14·1 answer
  • IF YOU HELP I'LL MARK AS BRAINLIEST
    5·2 answers
  • Geometry Angles help.<br><br> I need help with<br><br> What is "GE"
    10·1 answer
  • Which ordered pair satisfies the equation y =(-5)? A.(-6,1) B. (-2,7) C.(2,-7) D.(-1,-6)​
    12·1 answer
  • Which statement is most likely to be true for this distribution?
    6·1 answer
  • There are 12 navy bikes and 4 brown bikes in your dad's bikeshop.
    10·1 answer
  • What is the y=Mx+b of this equation
    6·1 answer
  • 5x-y=12 ............................
    15·1 answer
  • Find X: <br> J:58<br> K:70<br> L:111<br> M:121
    13·2 answers
  • After a gas-filled balloon is released, it rises 90 feet by the end of the first minute. by the end of the second minute, the ba
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!