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3 years ago

3x + 10 = 4x +54. How did you get your answer?

Mathematics

1 answer:

inysia [295]3 years ago

7 0

Answer:

$x=-44$

Step-by-step explanation:

$3x+10=4x+54$

To solve for the variable $x$ , start by subtracting $3x$ from both sides of the equation:

$10=x+54$

Then, subtract $54$ from both sides of the equation:

$-44=x$

Therefore, $x=-44$

To check your work, simply substitute the solved value of $x$ into the initial equation:

$3(-44)+10=4(-44)+54$

Multiply:

$-132+10=-176+54$

Add:

$-122=-122$

Since both sides of the equation are equal to each other, our solution is correct!

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Zoe goes out to lunch. The bill

DanielleElmas [232]

Answer:

$60

Step-by-step explanation:

To find how much Zoe paid before the sales tax and tip, we first need to consider the amount she paid in sales tax and tips.

Sales tax + Tips = $18.60

Let x = original price

Sales tax = 11% * original price

Sales tax = 0.11 * x

x= 0.11x

Tips = 20% * original price

Tips = 0.20 * x

x = 0.2x

Now that we have a value for both the sales tax and tips, we can then proceed to find the original price by:

0.11x + 0.2x = 18.60

0.31x = 18.60

Now we need to divide both sides by 0.31 to find x.

x = 60

Zoe's dinner before the sales tax and tips was $60.

5 0

3 years ago

Read 2 more answers

The service life of a battery used in a cardiac pacemaker is assumed to be normally distributed. A random sample of 10 batteries

Nat2105 [25]

Answer:

(1) We are conducting the one-sample t-test and will be testing for the hypothesis of mean battery greater than 25 h. So, we will reject the null hypothesis for mean battery life equal to 25 hr against the alternative hypothesis for mean battery life greater than 25 hr.

(2) A 95% lower confidence interval on mean battery life is 25.06 hr.

Step-by-step explanation:

We are given that a random sample of 10 batteries is subjected to an accelerated life test by running them continuously at an elevated temperature until failure, and the following lifetimes (in hours) are obtained: 25.5, 26.1, 26.8, 23.2, 24.2, 28.4, 25.0, 27.8, 27.3, and 25.7.

Firstly, the pivotal quantity for finding the confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean BAC = $\frac{\sum X}{n}$ = 26 hr

s = sample standard deviation = $\sqrt{\frac{\sum(X - \bar X)^{2} }{n-1} }$ = 1.625 hr

n = sample of batteries = 10

$\mu$ = population mean battery life

<em> Here for constructing a 95% lower confidence interval we have used a One-sample t-test statistics because we don't know about population standard deviation. </em>

(1) It is stated that the manufacturer wants to be certain that the mean battery life exceeds 25 h.

Since we are conducting the one-sample t-test and will be testing for the hypothesis of mean battery greater than 25 h. So, we will reject the null hypothesis for mean battery life equal to 25 hr against the alternative hypothesis for mean battery life greater than 25 hr.

(2) So, a 95% lower confidence interval for the population mean, $\mu$ is;

P(-1.833 < $t_9$ ) = 0.95 {As the lower critical value of t at 9