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Makovka662 [10]
3 years ago
9

A pharmacist has an 18% alcohol solution and a 40% alcohol solution. How much of each should he mix together to make 10 liters o

f a 20% alcohol solution?
Mathematics
1 answer:
TiliK225 [7]3 years ago
3 0
Lets call x the amount of 18% solution and y the amount of 40% solution, and write as equations the info of the problem:
18x + 40y = 10(20)
x + y = 10
lets multiply the second equation by -18 and add to the first:
 18x + 40y = 200
-18x -<span> 18y = -180
</span>----------------------
0 + 22y = 20
y = 20/22 = 10/11
and substitute in the original equation:
x <span>+ y = 10
</span>x = 10 - y
x = 10 - 10/11
x = 110/11 - 10/11
x = 100/11
so they have to use 100/11 liters of 18% solution and 10/11 liters of 40% solution
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Tim bought some 25 cent and some 29 cent stamps. He paid 7.60 dollars for 28 stamps. How many of each type of stamp did he buy?
Citrus2011 [14]

Answer:

25 cent stamps = 13 and 29 cent stamps = 15

Step-by-step explanation:

x = 25 cent stamps and y = 29 cent stamps

x + y = 28......x = 28 - y

0.25x + 0.29y = 7.60

0.25(28 - y) + 0.29y = 7.60

7 - 0.25y + 0.29y = 7.60

-0.25y + 0.29y = 7.60 - 7

0.04y = 0.60

y = 0.60 / 0.04

y = 15 <===== 29 cent stamps

x + y = 28

x + 15 = 28

x = 28 - 15

x = 13 <===== 25 cent stamps

lets check it...

0.25x + 0.29y = 7.60

0.25(13) + 0.29(15) = 7.60

3.25 + 4.35 = 7.60

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8 0
3 years ago
A pair of shoes cost $22.99 to make, the local store sells them for $36.99. What is the percent markup? (Round to the nearest hu
ASHA 777 [7]

C: 60.9% is the right answer

Step-by-step explanation:

The markup is calculated by using the formula

Mark\ up=Selling\ price-make\ price

Given

Make Price = $22.99

Selling Price = $36.99

So the mark up will be:

Mark\ up=36.99-22.99\\=\$14

Percent mark up will be:

Mark\ up=\frac{Mark\ up}{Make\ price}*100\\=\frac{14}{22.99}*100\\=0.6089*100\\=60.89\%

Rounding off to the nearest hundredth percent

60.9%

Hence,

C: 60.9% is the right answer

Keywords: Markup, Percentage

Learn more about percentage at:

  • brainly.com/question/10435836
  • brainly.com/question/10541435

#LearnwithBrainly

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3 years ago
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