An endurance athlete jogs at a rate of 8 miles per hour. How many minutes does it take for the athlete to jog 2.4 miles?

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

ladessa [460]

X = amount of the 18% solution

y = amount of the 40% solution

we know the 18% solution has only 18% of alcohol, the rest is maybe water or something, now, how many liters is 18%? well, 18% of anything is just (18/100) * anything, so, 18% of x is just (18/100) *x or 0.18x, and that's how many liters are there.

likewise, how many liters are there in the 40% solution? well, (40/100) * y, or 0.4y, that many.

we know the mixture has to yield 10 liters at 20% alcohol, how many liters of only alcohol is that? well, (20/100) * 10, or 2 liters.

$\bf \begin{array}{lccclll}
&\stackrel{liters}{amount}&\stackrel{alcohol~\%}{quantity}&\stackrel{liters}{alcohol}\\
&------&------&------\\
\textit{18\% solution}&x&0.18&0.18x\\
\textit{40\% solution}&y&0.40&0.4y\\
------&------&------&------\\
mixture&10&0.20&2
\end{array}$

$\bf \begin{cases}
x+y=10\implies \boxed{y}=10-x\\
0.18x+0.4y=2\\
----------\\
0.18x+0.4\left( \boxed{10-x} \right)=2
\end{cases}
\\\\\\
0.18x-0.4x+4=2\implies -0.22x=-2
\\\\\\
x=\cfrac{-2}{-0.22}\implies x=\cfrac{100}{11}\implies x=9\frac{1}{11}$

how much of the 40% solution? well y = 10 - x

3 0

3 years ago

I need help I am trying to find ft

Rus_ich [418]

1 foot = 12 inches

divide 69 by 12

69/12 = 5.75 feet

7 0

3 years ago

I need help finding the formula..

KiRa [710]

X=first week
y=second week
z=third week
t=fourth week

18 more one 2nd week than 1st
x+18=y
x=y-18

3rd week, 4 less than 2 times as second
z=2y-4

4th week, 92

ttal=382

x+y+z+t=382
sub waht we know
x=y-18
y=y
z=2y-4
t=92

y-18+y+2y-4+92=382
conbine line terms
4y+70=382
minus 70 boht sides
4y=312
divide both sides by 4
y=78

78 customers
for equation read my answer slowly

8 0

3 years ago

Some one help me on this one

aleksandrvk [35]

The answer is III only, or D.

We can start to solve this by knowing what the HL theorem means. The HL theorem, like its name implies, shows says that if a hypotenuse and leg of a triangle are congruent to the hypotenuse and leg of a different triangle, then the triangles are congruent. The only triangle that we see a hypotenuse congruent in is in figure III. In figure II, those congruent sides are both legs while in figure I we just see 2 congruent angles. Now in figure III, we can also see that two legs are congruent because of the reflexive property. That means that the answer is III, or D.

5 0

3 years ago

The following table gives results from two groups of students who took a nonproctored test. Use a 0.01 significance level to tes

Nana76 [90]

Answer:

Original claim is $\mu_{1} =\mu_{2}$

Opposite claim is $\mu_{1} \neq \mu_{2}$

Null and alternative hypotheses:

$H_{0}:\mu_{1} = \mu_{2}$

$H_{1} : \mu_{1} \neq \mu_{2}$

Significance level: 0.01

Test statistic:

We can use TI-84 calculator to find the test statistic and P-value. The steps are as follows:

Press STAT and the scroll right to TESTS

Scroll down to 2-SampTTest... and scroll to stats.

Enter below information.

$\bar{x_{1}}=70.29$

$Sx1=22.09$

$n_{1} = 30$

$\bar{x_{2}}=74.26$

$Sx2=18.15$

$n_{2} = 32$

$\mu_{1} \neq \mu_{2}$

Pooled: Yes

Calculate.

The output is in the attachment.

Therefore, the test statistic is:

$t=-0.78$

P-value: 0.4412

Reject or fail to reject: Fail to reject

Final Conclusion: Since the p-value is greater than the significance level, we, therefore, fail to reject the null hypothesis and conclude that the there is sufficient evidence to support the claim that the samples are from populations with the same mean.

6 0

3 years ago