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denis23 [38]
2 years ago
7

George wishes to increase the percent of acid in 50ml of a 15% acid solution in water to 25% acid, how much pure acid must you a

dd?
Mathematics
2 answers:
laiz [17]2 years ago
7 0

MARK BRAINLIEST

you have to add 6 and 2/3ml of pure acid

Step-by-step explanation:

common sense

Andreyy892 years ago
4 0
Amount times concentration=quantity

50(0.15)+x(1)=(50+x)(0.25)
x=amount of acid to add

so
7.5+x=12.5+0.25x
minus 0.25x both sides
7.5+0.75x=12.5
minus 7.5 both sides
0.75x=5
divide both sides by 0.75
x=6.666666666
converts to 6 and 2/3

you have to add 6 and 2/3ml of pure acid
You might be interested in
Find the amount of time.<br> I=$450, P=$2400, r=7.5%<br> Help!
faust18 [17]
I = PRT.....rearrange = I / PR = T
I = 450
R = 7.5%...turn to decimal = 0.075
P = 2400

I / (PR) = T
450 / (2400 * 0.075) = T
450 / 180 = T
2.5 = T...so time is 2.5 years, or 2 1/2 years
8 0
2 years ago
The heights of students at a college are normally distributed with a mean of 175 cm and a standard deviation of 6 cm. One might
frosja888 [35]

Answer:

25

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean = 175cm

Standard deviation = 6 cm

Percentage of students below 163 cm

163 = 175 - 2*6

So 163 is two standard deviations below the mean.

By the Empirical rule, 95% of the heights are within 2 standard deviations of the mean. The other 100-95 = 5% are more than 2 standard deviations of the mean. Since the normal distribution is symmetric, 2.5% of them are more than 2 standard deviations below the mean(so below 163cm) and 2.5% are more than two standard deviations above the mean.

2.5% of the students have heights less than 163cm.

Out of 1000

0.025*1000 = 25

25 is the answer

8 0
2 years ago
Read 2 more answers
A rectangular garden has a width that is 8 feet less than twice the length. Find the dimensions if the perimeter is 20 feet.
krok68 [10]

Answer:

length = 6 feet

width = 4 feet

Step-by-step explanation:

To find the dimensions of the rectangle, you can set up a variable and an expression that will equal the perimeter of the figure.  Given l = length, width is '8 feet less than twice the length' or w = 2l - 8.

The general formula for perimeter of a rectangle is:

2w + 2l = P, where w = width and l = length

Using the variable and expression from above and the perimeter of 20 feet:

2(2l - 8)+ 2l = 20

distribute: 4l - 16 + 2l = 20

combine like terms: 6l - 16 = 20

add 16 to both sides: 6l - 16 + 16 = 20 + 16 or 6l = 36

divide and solve for 'l':  6l/6 = 36/6, or l = 6 feet

solve for 'w':  w = 2(6) - 8 or w = 12 - 8 = 4 feet

4 0
2 years ago
George still has 40 percent of his book to read. If George has read 180 pages, how many pages does he still have to read? How do
beks73 [17]

Answer:  72

Step-by-step explanation:    so you do a line = line method the lines should look like they are fractions.  

you do it for the both numbers the percent is always out of 100.

it should look like this

40%            ?

--------- = -----------    

100%       180

then you cross multiply 40 and 180 and than divide it by 100.   your answer should be 72.    you later replace the ? with 72

you know this because It is smaller than 180 and its bigger than the number 40.

5 0
2 years ago
Mr. Abraham is 36 years old. His wife is 6 years younger than him and their son is 24 years old younger than his wife. What is t
sesenic [268]
Hi!
We know that Mr. Abraham’s wife is 6 years younger than him, which is 36-6, which means his wife is 30 years old.

We also know that Mr A’s son is 24 years younger than his wife, which is 30-24, which is 6.

As of right now, we now know that:
Mr. A is 36
Mr. A’s wife is 30
Mr. A’s son is 6

It’s asking for the ratio of Him:Wife:Son, so 36:30:6.

BUT, it’s asking for simplest form, so divide each of those numbers by 6.

Your answer is: 6:5:1
8 0
2 years ago
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