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3 years ago

10

During a race, Bernie ran 9 meters every 4 seconds, while Wendel ran 2 meters every second and got a 9-meter head start. If the

race was 70 meters long, did Bernie ever catch up with Wendel in the race?

1 answer:

Vsevolod [243]3 years ago

8 0

No, because Bernie had to run 9 meters 7.77777778 time (70/9) and each of those 9-meter sections took 4 seconds, so her time was 31.1111111 (7.77777778*4). While Wendel had to run 61 meters 70-his headstart (9 meters) (70-9). So he only had to run 30.5 blocks of 2 meters (61/2). And since they're only 1 second long, it's 30.5*1=30.5. The answer then is NO because (Bernie) 31.1111111 seconds > 30.5 seconds (Wendel).

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3 years ago

1/2(a+b)-(a-b)exponent2 when a=18 and b=14

lora16 [44]

Answer:

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Step-by-step explanation:

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3 years ago

Brewed decaffeinated coffee contains some caffeine. We want to estimate the amount of caffeine in 8 ounce cups of decaf coffee a

rusak2 [61]

Answer:

We would have to take a sample of 62 to achieve this result.

Step-by-step explanation:

Confidence level of 95%.

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1 - 0.95}{2} = 0.025$

Now, we have to find z in the Ztable as such z has a pvalue of $1 - \alpha$ .

That is z with a pvalue of $1 - 0.025 = 0.975$ , so Z = 1.96.

Now, find the margin of error M as such

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In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

Assume that the standard deviation in the amount of caffeine in 8 ounces of decaf coffee is known to be 2 mg.

This means that $\sigma = 2$

If we wanted to estimate the true mean amount of caffeine in 8 ounce cups of decaf coffee to within /- 0.5 mg, how large a sample would we have to take to achieve this result?

We would need a sample of n.

n is found when $M = 0.5$ . So

$M = z\frac{\sigma}{\sqrt{n}}$

$0.5 = 1.96\frac{2}{\sqrt{n}}$

$0.5\sqrt{n} = 2*1.96$

Dividing both sides by 0.5

$\sqrt{n} = 4*1.96$

$(\sqrt{n})^2 = (4*1.96)^2$

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Rounding up

We would have to take a sample of 62 to achieve this result.

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2 years ago

Angle Sum Theorem. y = ?

salantis [7]

Answer:

90°

Step-by-step explanation:

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11 months ago

If DM = 35, what is the value of r?

Gennadij [26K]

Answer:

$r = 11$

Step-by-step explanation:

Given

$DM = 35$

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Required

Find r

From the question, we understand that G is a point between D and M:

This implies that:

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Substitute values for DM, DG and GM

$35 = r + 5 + 3r - 14$

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$r = 44/4$

$r = 11$

3 0

3 years ago