Kay buys 12 pounds of apples. Each pound costs $3.if she gives the cashier two $20 bills, how much change should she receive.

What is the unit rate for 500.48 meters in 27.2 hours?

Daniel [21]

27.2h÷1h=27.2
500.48m in 27.2h
(÷27.2)
18.4 in 1h

Ans: 18.4m/h

4 0

1 year ago

A random sample of 250 students at a university finds that these students take a mean of 15.2 credit hours per quarter with a st

Orlov [11]

Answer:

95% confidence interval for the mean credit hours taken by a student each quarter is [14.915 hours , 15.485 hours].

Step-by-step explanation:

We are given that a random sample of 250 students at a university finds that these students take a mean of 15.2 credit hours per quarter with a standard deviation of 2.3 credit hours.

Firstly, the pivotal quantity for 95% 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 credit hours per quarter = 15.2 credit hours

s = sample standard deviation = 2.3 credit hours

n = sample of students = 250

$\mu$ = population mean credit hours per quarter

Here for constructing 95% confidence interval we have used One-sample t test statistics as we know don't about population standard deviation.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-1.96 < $t_2_4_9$ < 1.96) = 0.95 {As the critical value of t at 249 degree of

freedom are -1.96 & 1.96 with P = 2.5%}

P(-1.96 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 1.96) = 0.95

P( $-1.96 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $1.96 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-1.96 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+1.96 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-1.96 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+1.96 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $15.2-1.96 \times {\frac{2.3}{\sqrt{250} } }$ , $15.2+1.96 \times {\frac{2.3}{\sqrt{250} } }$ ]

= [14.915 hours , 15.485 hours]

Therefore, 95% confidence interval for the mean credit hours taken by a student each quarter is [14.915 hours , 15.485 hours].

The interpretation of the above confidence interval is that we are 95% confident that the true mean credit hours taken by a student each quarter will be between 14.915 credit hours and 15.485 credit hours.

8 0

1 year ago

Tony and Manuel were trimming the branches of a tree. Tony was using an 18 ft ladder and Manuel was using a 24 ft ladder. Both l

REY [17]

Answer:

9.33 feet = 111.96 inches

Step-by-step explanation:

If we have similar triangles, the rate between matching sides is the same.

So the length of the smaller ladder (18 ft) over the length of the taller ladder (24 ft) is equal to the distance from the bottom of the smaller ladder to the tree (7 ft) over the distance from the bottom of the taller ladder to the tree (x ft):

18 / 7 = 24 / x

x = 7 * 24 / 18

x = 9.33 feet

To find this measure in inches, we just need to multiply by 12:

x = 9.33 * 12 = 111.96 inches

3 0

2 years ago

During the first seconds after takeoff, a rocket traveled 208 kilometers in 50 minutes at a constant rate suppose a penny is dro

andrezito [222]

the penny travels at a faster rate by 56.4 kilometers

penny = 153 for 30 min

penny = 306 for 1 hour

rocket = 208 in 50 min

208/5 = 41.6 *6 = 249.6 in 1 hour

penny is faster by 56.4 kilometers

6 0

2 years ago

Mr. Johnson is going to buy an 18 3 4 pound turkey for Thanksgiving. The turkey costs $ 2.80 per pound at the grocery store. If

bezimeni [28]

Answer:

10.22 she save

Step-by-step explanation:

18 3/4 x 2.80=51.1

51.1 x 20%=10.22

4 0

1 year ago