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Lorico [155]
3 years ago
12

Two chemicals X and Y are to be mixed together to achieve a 16ml solution that is 7.4% water. Chemical x is 5% water and Y is 9%

water. How much Y should be used in the mix?
Mathematics
1 answer:
makvit [3.9K]3 years ago
8 0

Answer:

9.6 mL

Step-by-step explanation:

If x is mL of chemical X, and y is mL of chemical Y, then:

x + y = 16

0.05x + 0.09y = 0.074(16)

Solve the system of equations using substitution.

0.05(16 − y) + 0.09y = 0.074(16)

0.8 − 0.05y + 0.09y = 1.184

0.04y = 0.384

y = 9.6

You need 9.6 mL of Y.

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Compute the standard deviation of the following set of data to the nearest whole number:
Klio2033 [76]

Answer:

Step-by-step explanation:

The standard deviation is the square root of the variance, and the variance is found by using the mean. So we will do that first. I will use the population variance as opposed to the sample variance since our set of numbers is small.

The mean: 8 + 12 + 15 + 17 + 18 = 70 and divide that by 5 to get

\bar{x}=14 and use this to find the variance in the formula:

s^2=\frac{\sum(x_i-\bar{x})^2}{n} it is a bit difficult to enter that formula in correctly, but here's how it works mathematically:

s^2=\frac{(8-14)^2+(12-14)^2+(15-14)^2+(17-14)^2+(18-14)^2}{5}

Squaring this ensures us that we don't end up with zero, which would be useless.

s^2=\frac{36+4+1+9+16}{5} so

s^2=13.2 which means that the standard deviation is

s = 3.633

(If you do it with n-1 = 4 in the denominator of the variance, you get a standard deviation of 4.062)

3 0
3 years ago
Step by step explanation thanks
ratelena [41]

Answer:

75%

Step-by-step explanation:

\frac{90}{120}*100=\frac{9}{12}*100=\frac{3}{4}*100=3*25=75%%

7 0
3 years ago
Sam drove for 2 hours at 45 mph. He has the same distance remaining. How fast should he drive to make his average speed 60 mph?
Goshia [24]
Speed (S) = Distance (D) / time (t)

First stretch

45 = D / 2

D = 45*2

D = 90 mp

How is the same distance:

Second stretch

S = 90 / t

Average speed (AS):

AS = (S1+S2) / 2

60 = [45+(90/t)] / 2

120 = 45+90/t

120-45 = 90/t

75 = 90/t

t = 90/75

t = 1,2 h

________________________

And now:

S = 90 / t

S = 90 / 1,2

S = 75 mph
8 0
3 years ago
Robin invests $3,210 in an account that is compounded annually and pays
igor_vitrenko [27]

Answer:

the factor is an increasing value of 17/332 or the power of pointed answers of interest of 3.4% which makes it aroujd 2 but doesnt matter because its the factor and not issued investment

Step-by-step explanation:

8 0
3 years ago
What is the value of the discriminant, b2 − 4ac, for the quadratic equation 0 = x2 − 4x + 5, and what does it mean about the num
forsale [732]
(-4)^2-4(1)(5)
16-4(1)(5)
16-4(5)
16-20
-4

The discriminant is negative so there are no real number solutions.
3 0
3 years ago
Read 2 more answers
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