I need help on these two questions

A group of friends went out for dinner and decided to split the cost of the bill equally. If each person contributed $32, the fr

lianna [129]

Answer:

The number of friends that went out for dinner is 8

And their bill is $238

Step-by-step explanation:

Let's assume that the number of friends that went out for dinner to be x

And the bill for the dinner to be y

If each person contributed $32 and paid off the bill,they will have a balance of $18

32x - 18 = y_____equation 1

If each person contributed $35 and paid off the bill and also 15% tip,they will have a balance of $6.30

35x - 6.3 = y + (15% of y)

35x - 6.3 = y + (3y/20)

Open up the bracket

35x - 6.3 =(20y + 3y)/20

700x - 126 = 23y______equation 2

From equation 1,y = 32x - 18

Put the above in equation 2 and we have

700x - 126 = 23(32x -18)

700x - 126 = 736x - 414

collect like terms

36x = 288

x = 288/36

x = 8

Remember that equation 1 says that y = 32x - 18 and we now know that x = 8 .

Substitute and we have

(32 × 8) - 18

y = 238

The number of friends that went out for dinner is 8

And their bill is $238

3 0

3 years ago

AARP reported on a study conducted to learn how long it takes individuals to prepare their federal income tax return (AARP Bulle

Crank

Answer:

Confidence interval: (30.1,36.9)

Step-by-step explanation:

We are given the following data set:

35.3,30.5,37.4,26.5,13.0,49.9,28.8,44.0,61.6,0.5,40.5,34.9,47.9,36.6,24.1,39.8,47.8,18.5,36.6,39.2,14.5,37.3,40.5,49.3,45.5,28.3,19.5,5.6,52.6,41.4,45.3,39.0,33.7,29.4,14.5,40.1,33.7,36.9,5.6,33.7

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.

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

$Mean =\displaystyle\frac{1339.9}{40} = 33.5$

$S.D = 11$ (given)

n = 40

Confidence interval:

$\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}$

Putting the values, we get,

$z_{critical}\text{ at}~\alpha_{0.05} = 1.96$

$33.5 \pm 1.96(\frac{11}{\sqrt{40}} ) = 6.34 \pm 3.4 = (30.1,36.9)$

6 0

3 years ago

68+(-41)=? Solved and show how you got the answer.

mars1129 [50]

Answer:

27

Step-by-step explanation:

68 + (-41) = ?

Well, adding a negative is the same as subtracting a positive, so...

68 + (-41) = 68 - 41

68 - 41 = 27

7 0

3 years ago

Read 2 more answers

A person's blood glucose level and diabetes are closely related. Let x be a random variable measured in milligrams of glucose pe

soldier1979 [14.2K]

Using the normal distribution, it is found that:

a) 0.8599 = 85.99% probability that x is more than 60.

b) 0.1788 = 17.88% probability that x is less than 110.

c) 0.6811 = 68.11% probability that x is between 60 and 110.

d) 0.0643 = 6.43% probability that x is greater than 125.

In a normal distribution with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

It measures how many standard deviations the measure is from the mean.
After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.

In this problem: