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4 years ago

A pile of 55 coins, consisting of nickels and dimes, is worth $3.90. find the number of each.

2 answers:

5 0

Answer is: 32 nickels and 23 dimes.
x - number of nickels .
y -number of dimes.
two equations in two unknowns:
1) x + y = 55
2) 0,05x + 0,1y = 3,90.
nickel is a five-cent coin.
dime is a ten-cent coin.
solve equation 1) for x and substitute for x in equation 2)
x = 55 - y
0,05·(55 - y) + 0,1y = 3,902,75 - 0,05y + 0,1y = 3,90
0,05y = 1,15
y = 23.
x = 55 - 23 = 32.

Leto [7]4 years ago

3 0

Answer:

Answer is: 32 nickels and 23 dimes.

x - number of nickels .

y -number of dimes.

two equations in two unknowns:

1) x + y = 55

2) 0,05x + 0,1y = 3,90.

nickel is a five-cent coin.

dime is a ten-cent coin.

solve equation 1) for x and substitute for x in equation 2)

x = 55 - y

0,05·(55 - y) + 0,1y = 3,902,75 - 0,05y + 0,1y = 3,90

0,05y = 1,15

y = 23.

x = 55 - 23 = 32.

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The average systolic blood pressure was found to be 140 mm for people who have high responsibility jobs, specifically investment

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Answer:

t = -1.428

Step-by-step explanation:

Average blood pressure among people with high responsibility jobs = u = 140 mm

Number of people sampled for the study = n = 51

Average blood pressure of the sample = x = 139 mm

Standard deviation of the sample = s = 5 mm

The claim is that practicing yoga decreases the blood pressure. So we have to test that after practicing yoga, the average blood pressure will be lesser than 140. Based on this we can formulate the null and alternate hypothesis as:

Null Hypothesis: $\mu \geq 140$

Alternate Hypothesis: $\mu < 140$

Since population standard deviation is not known, we cannot use z-distribution for this test. We are given the value of sample standard deviation, so t-test will be used for this case.

Test statistic is calculated as:

$t=\frac{x-u}{\frac{s}{\sqrt{n} } }$

Using the values in this formula gives us:

$t=\frac{139-140}{\frac{5}{\sqrt{51}}}\\\\ t=-1.428$

Therefore, the value of test statistic is -1.428

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3 years ago

In a certain Algebra 2 class of 27 students, 5 of them play basketball and 12 of them

alekssr [168]

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3 years ago

Segment BD is an altitude of triangle ABC. Find the area of the triangle.

Sever21 [200]

Answer: The correct option is A, i.e., 7.5.

Explanation:

It is given that ABC is a triangle and BD is an altitude.

Since BD is an altitude, therefore the height of the triangle is BD and the base of the triangle is AC.

The distance formula to find the distance between two points is,

$D=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

First, we find BD, where B(-1,4) and D(2,4).

$BD=\sqrt{(2+1)^2+(4-4)^2}=\sqrt{9} =3$

So, the height of the triangle is 3.

Now, we find the value of AC, where A(2,1) and C(2,6).

$AC=\sqrt{(6-1)^2+(2-2)^2}=\sqrt{25} =5$

So, the base of the triangle is 5.

The formula to find the area of a triangle is,

$A=\frac{1}{2}\times {\text{base}}\times {\text{height}}$

$A=\frac{1}{2}\times 5\times 3=\frac{15}{2}=7.5$

Therefore, the area of the triangle is 7.5 unit square and the correct option is A.

6 0

3 years ago

Read 2 more answers

Write the equation of a line in slope intercept form of a line that has a slope of 5 and a y

xenn [34]

Answer: y=5x-8

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3 years ago

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Marina CMI [18]

Answer:

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I hope this helps :)

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3 years ago