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Mekhanik [1.2K]

2 years ago

15

Pamela drove her car 99 kilometers and used 9 liters of fuel. She wants to know how many kilometers (k) she can drive with 12 li

ters of fuel. She assumes the relationship between kilometers and fuel is proportional.
How many kilometers can Pamela drive with 12 liters of fuel?

2 answers:

masya89 [10]2 years ago

7 0

Answer:

132 kilometers

Step-by-step explanation:

Given: Pamela drove her car 99 kilometers and used 9 liters of fuel.

To find: Number of kilometers Pamela drove in 12 liters of fuel.

Solution:

It is given that Pamela drove her car 99 kilometers and used 9 liters of fuel. Also the relationship between kilometers and fuel is proportional.

So, let us assume that she can travel x kilometers in 12 liters of fuel.

By proportionality we have,

$99:9 :: x:12$

$\frac{99}{9} =\frac{x}{12}$

$11=\frac{x}{12}$

$x=12\times11$

$x=132$

Hence, she can travel 132 kilometers in 12 liters of petrol.

NNADVOKAT [17]2 years ago

7 0

Answer:

132 km on 12 liters.

Step-by-step explanation:

Just set up the proportion.

99 km : 9 liters :: x : 12 liters. Change this to an equation.

99/ 9 = x/12 Divide the left

11 = x / 12 Multiply both sides by 12

11 * 12 = x/12 *12 Combine the left and cancel the right.

132 = x

She can drive 132 km on 12 liters.

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2 years ago

Times for an ambulance to respond to a medical emergency in a certain town are normally distributed with a mean of 400 seconds a

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Answer:

Step-by-step explanation:

In the normal distribution curve, the mean is in the middle and each line to the left and to the right of that mean represent 1- and 1+ the standard deviation. If our mean is 400, then 400 + 50 = 450; 450 + 50 = 500; 500 + 50 = 550. Going from the mean to the left, we subtract the standard deviation and 400 - 50 = 350; 350 - 50 = 300; 300 - 50 = 250. We are interested in the range that falls between 350 and 450 as a percentage. That range represents the two middle sections, each containing 34% of the data. So the total percentage of response times is 68%. We are looking then for 68% of the 144 emergency response times in town. .68(144) = 97.92 or 98 emergencies that have response times of between 350 and 450 seconds.

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2 years ago

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A customer visiting the suit department of a certain store will purchase a suit with probability .22, a shirt with probability .

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Answer:

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Step-by-step explanation:

lets call su the event that the customer purchases a suit, sh the event that teh customer purchases a shirt and t the event that the customer purchases a tie.

Remembe that for events A, B and C we have that

P(A U B) = P(A) + P(B) - P(A ∩ B)

P(A U B U C) = P(A) + P(B) + P(C) - P(A ∩ B) - P(A ∩ C) - P(B ∩ C) + P(A ∩ B ∩ C)

Also, we are given that

P(su) = 0.22

P(sh) = 0.3

p(t) = 0.28

p(su ∩ sh) = 0.11

P(su ∩ t) = 0.14

P(sh ∩ t) = 0.1

P(sh ∩ t ∩ su) = 0.06

The event that he doesnt buy any item has as complementary event su ∪ sh ∪ t, therefore

P( he doesnt but any items) = 1-P(su U sh U t) =

1-( P(su) + p(sh) + p(t) - P(su ∩ sh) - p(su∩t) - p(sh∩t) + p(su∩sh∩t) ) =

1-(0.22+0.30+0.28-0.11-0.14-0.1+0.06) = 1-0.51 = 0.49

b) The probability that he buys at least 2 items is equal to

p(su ∩ t) + p(su ∩ sh) + p(sh ∩ t) -2 p(su ∩ t ∩ sh) (because we are counting the triple intersection 3 times, so we need to remove it twice)

This number is

0.14+0.11+0.1-2*0.06 = 0.23

Thus, the probability that he buys exactly one item can be computed by substracting from one the probability of the complementary event : she buys 2 or more or non items

P(he buys exactly one item) = 1- ( p(he buys none items) + p(he buys at least 2) ) = 1- 0.49-0.23 = 0.28

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Answer:

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Step-by-step explanation:

To solve this question, we have to understand the normal probability distribution and the central limit theorem.

Normal probability distribution:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

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

The Z-score 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. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central limit theorem:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sample means of size n can be approximated to a normal distribution with mean $\mu$ and standard deviation, which is also called standard error $s = \frac{\sigma}{\sqrt{n}}$

In this problem, we have that:

$\mu = 3.8, \sigma = 0.2, n = 4, s = \frac{0.2}{\sqrt{4}} = 0.1$

What is the blood potassium level L such that the probability is only 0.05 that the average of four measurements is less than L?

This is the value of X when Z has a pvalue of 0.05. So it is X when Z = -1.645.

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

By the Central Limit Theorem

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

$-1.645 = \frac{X - 3.8}{0.1}$

$X - 3.8 = -1.645*0.1$

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The blood potassium level L such that the probability is only 0.05 that the average of four measurements is less than L is 3.64.

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2 years ago

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First we need to change it in 'oz'.

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It becomes,

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First it becomes,

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At last it becomes,

$\frac{196704}{3071}\\\\=64.1\ oz$

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c) 64.1 oz

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2 years ago

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