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
Gemiola [76]
3 years ago
11

I need help with this word problem it’s urgent please help.

Mathematics
1 answer:
harkovskaia [24]3 years ago
3 0

Starting with some solution of volume <em>v</em> and an alcohol concentration of 100<em>c </em>% , if you add 180 mL of 45% isopropyl to it, you get a mixture with a total volume of 180 mL + <em>v</em>.

Each mL of the starting solution contains <em>c</em> mL of alcohol. For example, if the concentration of the starting solution is 80% (so <em>c</em> = 0.8), then each mL contains 80% = 0.8 of one mL of alcohol.

Similarly, each mL of the added solution with 45% concentration contains 0.45 mL of alcohol.

You want the new solution to have a concentration of 70%, so that the ratio of the amount of alcohol in it to the total volume is 70%, meaning

<em>cv</em> + 0.45 (180 mL) = 0.7 (180 mL + <em>v</em>)

and you want to solve for <em>v</em> :

<em>cv</em> + 81 mL = 126 mL + 0.7<em>v</em>

<em>cv</em> - 0.7<em>v</em> = 126 mL - 81 mL

(<em>c</em> - 0.7) <em>v</em> = 45 mL

<em>v</em> = (45 mL) / (<em>c</em> - 0.7)

Judging by context clues, <em>c</em> lies somewhere between 0.7 and 1. (It can't be less than 0.7 because mixing this solution with any other solution of smaller concentration will never yield a solution of higher concentration.)

If, for example, <em>c</em> = 0.8, so that your starting solution is at 80% concentration, then you would need

<em>v</em> = (45 mL) / (0.8 - 0.7) = 450 mL

to be mixed with 180 mL of 45% solution to end up with 180 mL + 450 mL = 630 mL of 70% solution.

As another example, if you're mixing pure alcohol, so that <em>c</em> = 1, you would need

<em>v</em> = (45 mL) / (1 - 0.7) = 150 mL

to make a 180 mL + 150 mL = 330 mL batch of 70% solution. The fact that you would need less of a higher concentration solution is not surprising.

You might be interested in
A child throws a ball with a speed of 5 feet per second at an angle of 73 degrees with the horizontal. Express the vector descri
maxonik [38]

Answer:

  v = 5cos(73°)i +5sin(73°)j

Step-by-step explanation:

The components of the velocity vector are ...

  horizontal (i direction): 5·cos(73°)

  vertical (j direction): 5·sin(73°)

Then the velocity vector is the sum of these component vectors:

  v = 5cos(73°)i +5sin(73°)j

3 0
3 years ago
240 fl oz =how many c?
Lady_Fox [76]
30 cups, because, 1 fl oz equals 0.125 cups, I hope this helped! :)
8 0
3 years ago
Plz help before 11:59 pm I will mark brainliest
olganol [36]

Answer:

1.- 140 in²

2.- 2.25 in²

3.- 43.25 in²

4.- 7.5 in²

5. 349.75 in²

Step-by-step explanation:

4 congruent triangles mean 4 triangles same measurement

area 1 triangle=(B*H)/2=(10*7)/2=35in²

for area of the roof are 4 by area 1 triangle=4*35=140 in²

2.- area hole. Hole is a square so area Is side by side

area=1.5*1.5=2.25

3.- area front except the hole. As the side of front is isosceles trapezoide which it’s area is (B1+B2)H/2 where B1=8 in and B2=5 in and H=7 in

so arera with hole=(8+5)*7/2=45.5 in²

7 0
3 years ago
Read 2 more answers
Please help me with this urgenttlyyyyyy
Kazeer [188]

Answer: Just drag each box over to the other box

Step-by-step explanation:

just how i said

6 0
3 years ago
Several intervals can be combined into one region using the "set union" operation, ∪∪, which is represented as "u" in webwork. f
alekssr [168]

Write the set of points from  -6 to 0 but excluding  -4  and 0 as a union of intervals

First we take  the interval  -6 to 0. In that -4  and 0 are excluded.

So we split the interval -6 to 0.

Start with -6 and go up to -4. -4 is excluded so we break at -4. Also we use parenthesis for -4.

Interval becomes [-6,-4) . It says -6 included but -4 excluded.

Next interval starts at -4 and ends at 0. -4 and 0 are excluded so we use parenthesis not square brackets

(-4,0)

Now we take union of both intervals

[-6,-4) U (-4,0)  --- Interval from  -6 to 0 but excluding  -4  and 0



7 0
3 years ago
Other questions:
  • What’s the probability of drawing a jack on the first draw and a 3 on the second draw
    11·1 answer
  • David drops a ball from a bridge at an initial height of 100 meters.
    6·1 answer
  • Simplify the expression (4x − 3)(x + 5). 4x2 − 17x + 15 4x2 − 17x − 15 4x2 + 17x + 15 4x2 + 17x − 15
    9·2 answers
  • Which statement describes how the graph of the given polynomial would change if the term 2x5 is added?
    13·2 answers
  • What is the value of 3x divided by (10 - x) when 2x + 5 = 85
    5·1 answer
  • Last year Jo paid £245 for her car insurance. This year she has to pay £883 for her car insurance. Work out the percentage incre
    9·1 answer
  • Which container holds more a half gallon milk jug or 2 liter juice
    8·1 answer
  • Which statements are true? Select all that apply.
    7·2 answers
  • Plz help will give brainliest if correct
    7·2 answers
  • Please answer the following question
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!