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3 years ago

When a number is decreased by 10% of itself the result is 171. What is the number?

1 answer:

4 0

$100\%-10\%=90\%\\\\ \begin{array}{ccc}90\%&-&171\\\\100\%&-&x\end{array}\\\\cross\ multiply\\\\90x=171\times100\\\\90x=17100\ \ \ |divide\ both\ sides\ by\ 90\\\\\boxed{x=190}\leftarrow solution$

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Two trains, Train A and Train B weigh a total of 349 tons. Train A is heavier than Train B. The difference in their weights is 2

Ainat [17]

Answer:

Train A = 299 tons Train B = 50 tons

Step-by-step explanation:
Train A = x

Train B = y

x+y = 349

x= y +249

Plug in one equation into another

y+249+y= 349

Simplify

2y+249=349

Subtract 249 from both sides

2y=100

Divide both sides by 2

y=50

Plug it into the x equation to solve for x

x+50=349

-50 from both sides

x=299

3 0

3 years ago

What is the value of b2 - 4ac for the following equation? 2x 2 - 2x - 1 = 0

Orlov [11]

For you to make an equation a quadratic equation, you need everything to be on one side, so you add one to both sides.

2x^2 + 3x + 0=0 

a=2, b=3, c=0 

b^2-4ac (In the next step just plug in your variables) 

3^2 - 4(2)(0) 

9 - 8(0) 

9 - 0 

Your answer=9

6 0

3 years ago

Before every flight, the pilot must verify that the total weight of the load is less than the maximum allowable load for the ai

ss7ja [257]

Answer:

The probability that the plane is oveloaded is P=0.9983.

The pilot should take out the baggage and send it in another plain or have less passengers in the plain to not overload.

Step-by-step explanation:

The aircraft will be overloaded if the mean weight of the passengers is greater than 163 lb.

If the plane is full, we have 41 men in the plane. This is our sample size.

The weights of men are normally distributed with a mean of 180.5 lb and a standard deviation of 38.2.

So the mean of the sample is 180.5 lb (equal to the population mean).

The standard deviation is:

$\sigma=\frac{\sigma}{\sqrt{N}} =\frac{38.2}{\sqrt{41}}=\frac{38.2}{6.4} =5.97$

Then, we can calculate the z value for x=163 lb.

$z=\frac{x-\mu}{\sigma}=\frac{163-180.5}{5.97}=\frac{-17.5}{5.97}= -2.93$

The probability that the mean weight of the men in the airplane is below 163 lb is P=0.0017

$P(\bar X$

Then the probability that the plane is oveloaded is P=0.9983:

$P(overloaded)=1-P(X$

The pilot should take out the baggage or have less passengers in the plain to not overload.

7 0

4 years ago

To order the right amount of flooring, you need to know the floor area of the living room shown below. What is that area, in squ

sveta [45]

What is the shape of the floor in the living room? And what are the measurements?

4 0

4 years ago

Until recently a number of professions were prohibited from advertising. In 1977, the U.S. Supreme Court ruled that prohibiting

umka2103 [35]

Answer:

the two groups differed in their attitudes toward advertising, significantly

Step-by-step explanation:

given that until recently a number of professions were prohibited from advertising. In 1977, the U.S. Supreme Court ruled that prohibiting doctors and lawyers from advertising violated their right to free speech. The paper "Should Dentists Advertise?" Journal of Advertising Research, June 1982) compared the attitudes of 101 consumers and 124 dentists to the questions "I favor the use of advertising by dentists to attract new patients".

Hypotheses would be

H-0: the groups do not differ

H-a: The two groups differ significantly

(two tailed chi square test)

Observed

Group Strongly agree Agree Neutral Disagree Strongly disagree Total

Consumers 34 47 9 6 5 101

Dentists 9 18 23 28 46 124

Expected is calculated as row total * column total / grand total for each cell

chi square = (obs - exp)^2/Exp for each cell added

chi square = 79.2716

rxc 5x2

df = 4x1 =4

p value <0.00001

Since p < alpha say 0.01, we reject null hypothesis.

the two groups differed in their attitudes toward advertising, significantly

3 0

3 years ago