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3 years ago

7

Mr adkins has 2 packages, each with 6 batteries. He uses 4 of the batteries in a flashlight . How many batteries does he have le

ft?

2 answers:

Readme [11.4K]3 years ago

8 0

Answer:

8

Step-by-step explanation:

2 x 6 = 12

12 - 4 = 8

So, our answer is 8.

Brilliant_brown [7]3 years ago

7 0

Answer:

8

Step-by-step explanation:

6+6=12 , 12-4=8

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3 years ago

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The Barnes family has a coupon for 10% off their dinner. If their bill comes to $82.50 and they wish to tip 15%, what will they

satela [25.4K]

Answer:

Total cost= $86.25

Step-by-step explanation:

Giving the following information:

Discount= 10%

Nill= $82.5

Tip= 15%

<u>First, we need to calculate the discounted price:</u>

Discount price= 82.5 / 1.1= $75

<u>Now, the tip:</u>

Tip= 75*0.15= $11.25

<u>Finally, the total cost:</u>

Total cost= 75 + 11.25

Total cost= $86.25

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3 years ago

Set up and solve the following using dimensional analysis.

Softa [21]

1). Multiply (5400 inches) by (1 foot / 12 inch) then by (1 mile / 5280 foot).

(See explanation at the bottom)

= (5400 inch) x (1 foot / 12 inch) x (1 mile / 5280 foot)

= (5400 x 1 x 1 / 12 x 5280) (inch - foot - mile / inch - foot)

= 0.0852 mile

2). Multiply (16 week) by (7 day/week) then by (24 hour/day)
then by (60 minute/hour) then by (60 sec/minute).

3). Multiply (54 yards) by (3 foot/yard) then by (1 meter/3.28 foot)
and then by (1000 mm/meter)

4). Multiply (36 cm/second) by (3600 second/hour) then by (1 meter/100 cm)
then by (1 mile/1609.3 meter).

5). Look up how many grams in a pound ('P')
Look up how many mL in a gallon ('G')

Multiply (1.09 g/mL) by ( 1 pound/ P gram) then by (1 gallon/ G mL)

6). Multiply (32 foot/sec) by (1 meter / 3.28 foot) then by (60 sec/minute).

Each time I told you to multiply by something, it was always a fraction
where the numerator and denominator are equal, like (60 seconds/minute)
or (1 foot / 12 inch). Since the top and bottom of the fraction are equal, the
value of the fraction is ' 1 ' , and multiplying by it doesn't change the value,
it only changes the units ... that's what this whole exercise is about.
When you multiply, KEEP the units in the product, and then, after you multiply, you can 'cancel' units out of the top and bottom of the product.
Like if you have 'feet' on top and bottom, just cross them out. When you're done, if you did it correctly, the last unit you end up with will be the one you want.

4 0

3 years ago

A self proclaimed psychic was tested for ESP. The psychic was presented with 200 cards face down and asked to determine if the c

swat32

Answer:

The 95% confidence interval would be given (0.172;0.288).

We are confident at 95% that the true probability that the psychic correctly identifies the symbol on the card in a random trial is between (0.172;0.288).

We can conclude that her random guessing would have got her correct 20% of the time. Since the confidence interval contains 0.2, she has no psychic powers, rather she just guessed it like normal people. Any person could have got it correct this many times.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Description in words of the parameter p

$p$ represent the probability that the psychic correctly identifies the symbol on the card in a random trial

$\hat p$ represent the estimated probability that the psychic correctly identifies the symbol on the card in a random trial

n=200 is the sample size required

$z_{\alpha/2}$ represent the critical value for the margin of error

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

Numerical estimate for p

In order to estimate a proportion we use this formula:

$\hat p =\frac{X}{n}$ where X represent the cases successful

$\hat p=\frac{46}{200}=0.23$ represent the estimated probability that the psychic correctly identifies the symbol on the card in a random trial

Confidence interval

The confidence interval for a proportion is given by this formula:

$\hat p \pm z_{\alpha/2} \sqrt{\frac{\hat p(1-\hat p)}{n}}$

For the 95% confidence interval the value of $\alpha=1-0.95=0.05$ and $\alpha/2=0.025$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=1.96$

And replacing into the confidence interval formula we got:

$0.23 - 1.96 \sqrt{\frac{0.23(1-0.23)}{200}}=0.172$

$0.23 + 1.96 \sqrt{\frac{0.23(1-0.23)}{200}}=0.288$

And the 95% confidence interval would be given (0.172;0.288).

We are confident at 95% that the true probability that the psychic correctly identifies the symbol on the card in a random trial is between (0.172;0.288).

We can conclude that her random guessing would have got her correct 20% of the time. Since the confidence interval contains 0.2, she has no psychic powers, rather she just guessed it like normal people. Any person could have got it correct this many times.

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3 years ago

At noon (12:00 p.m.), three girls began jogging from the 0 -mile mark of a trail. Each girl jogged at her own steady pace. Drag

Dimas [21]

Cindy: 4mph
Taylin: 4m/30 min : 8 mph
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