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2 years ago

Giuliana has 22 quarters and dollar coins worth a total of $10.75.

2 answers:

7 0

Use the letters q and d to represent # of quarters and # of dollars.

q + d = 22 coins.

$0.25q + $1.00d = $10.75 Mult. this by 100 to eliminate fractions:
25q + 100d = 1075

Subst. q = 22 - d into the 2nd equation:

25 (22 - d) + 100 d = 1075

550 - 25d + 100d = 1075
550 + 75d = 1075
75 d = 525
d = 7

q + d = 22, so if d = 7, then q = 22-7, or q=15.

There are 15 quarters and 7 dimes.

Ad libitum [116K]2 years ago

4 0

Let

q------> the number of quarters coins

d------> the number of dollars coins

we know that

$1\ quarter=\$0.25$

$q+d=22$

$q=22-d$ ------> equation A

$0.25q+d=10.75$ -----> equation B

substitute equation A in equation B

$0.25[22-d]+d=10.75$

therefore

<u>the answer is the option</u>

$0.25[22-d]+d=10.75$

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The power P of a jet of water is jointly proportional to the cross sectional area A and to the cube ofthe velocity V. (a) Write

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Answer:

a) $P=kAV^3$

b) 54

Step-by-step explanation:

If one quantity, A, is jointly proportional to other 2 quantities (B & C), we can write proportionality equation as:

$A=k*B*C$

Where

k is the proportionality constant

Now, for this problem, P is jointly proportional to A and CUBE OF V, so we can write:

$P=kAV^3$

Now velocity, V, is triples, which means it becomes 3V

Also, cross sectional area, A, is doubled, which means it becomes 2A

Let's put these into formula and see the difference:

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1 year ago

Enya walked 2 km 309 m from school to the store. Then, she walked from the store to her home. If she

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Her home was 2 km 691 m from the store. (5 km = 5000m --> 5000-2309)

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2 years ago

A Washington, D.C., "think tank" announces the typical teenager sent 67 text messages per day in 2017. To update that estimate,

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Answer:

We reject the null hypothesis and fail to accept it and update that estimate that typical teenager sent does not 67 text messages per day.

Step-by-step explanation:

We are given the sample:

51, 175, 47, 49, 44, 54, 145, 203, 21, 59, 42, 100

Formula:

$\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}$

where $x_i$ are data points, $\bar{x}$ is the mean and n is the number of observations.

$Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}$

$Mean =\displaystyle\frac{990}{12} = 82.5$

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$S.D = \sqrt{\frac{3539.363636}{11}} = 59.5$