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3 years ago

4/15 + 7/9 whats the sum

Mathematics

2 answers:

JulijaS [17]3 years ago

7 0

Answer:

Step-by-step explanation:

54/45 = 1 9/45 = 1 1/5

which is one and one fifth

Effectus [21]3 years ago

7 0

Answer:

47/45 = 1 2/45

Step-by-step explanation:

- If you would like a more in-depth explanation please let me know. Hope this helps!

- First you have to find a common denominator. This will be 45.

- Now, figure out what you multiply to get 45. For example...

4 = 12 + 7 = 35 (add these up)

15 45 9 45 It should equal 47/45 = 1 2/45.

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Solve 7x+2y=16 5x-2y=20 x= y= (3 marks)

sasho [114]

X=3 and y=-5/2. Here is why, when we do 7x+5x that gives us 12x. -2y+2y=0 and then we have 16 plus 20 which gives us 36. Now we gotta isolate x which right now we have 12x=36. Therefore divide by 12 to get x alone, which 36 divided by 12 is equal to 3. X=3. Plug it back into the equation, 7(3)=21 plus 2y=16. Subtract 21 from both sides 16-21 is equal to -5. Then 2y=-5 divide by 2 on both sides you will have -5/2=y or y=-5/2. Hope this helps!

8 0

2 years ago

Steve paid $62 for groceries last week. That was $6.75 more then he spent this week. How much did Steve spend this week?

yarga [219]

the answer is to 62-6.75 is 55.25

6 0

2 years ago

Read 2 more answers

Please help!!!!!!!!!!!

boyakko [2]

Answer:

(7√6)/2

Step-by-step explanation:

The side ratios in these special triangles are ...

30°-60°-90° triangle: 1 : √3 : 2

45°-45°-90° triangle: 1 : 1 : √2

This tells you the length of the horizontal line is 7√3, and the value of x is ...

(7√3)/√2 = (7√6)/2

_____

Additional comment

Call the length of the horizontal line "y". Then the given ratios tell you ...

7 : y = 1 : √3 ⇒ y/7 = √3/1 ⇒ y = 7√3

and

x : y = 1 : √2 ⇒ x/y = 1/√2 ⇒ x = y/√2

When we rationalize the denominator, we get ...

x = (y√2)/2 = ((7√3)√2)/2 = (7√6)/2

4 0

2 years ago

An article in The Engineer (Redesign for Suspect Wiring," June 1990) reported the results of an investigation into wiring errors

GarryVolchara [31]

Answer:

a) The 99% confidence interval on the proportion of aircraft that have such wiring errors is (0.0005, 0.0095).

b) A sample of 408 is required.

c) A sample of 20465 is required.

Step-by-step explanation:

Question a:

In a sample with a number n of people surveyed with a probability of a success of $\pi$ , and a confidence level of $1-\alpha$ , we have the following confidence interval of proportions.

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

z is the zscore that has a pvalue of $1 - \frac{\alpha}{2}$ .

Of 1600 randomly selected aircraft, eight were found to have wiring errors that could display incorrect information to the flight crew.

This means that $n = 1600, \pi = \frac{8}{1600} = 0.005$

99% confidence level

So $\alpha = 0.01$ , z is the value of Z that has a pvalue of $1 - \frac{0.01}{2} = 0.995$ , so $Z = 2.575$ .

The lower limit of this interval is:

$\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.005 - 2.575\sqrt{\frac{0.005*0.995}{1600}} = 0.0005$

The upper limit of this interval is:

$\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.005 + 2.575\sqrt{\frac{0.005*0.995}{1600}} = 0.0095$

The 99% confidence interval on the proportion of aircraft that have such wiring errors is (0.0005, 0.0095).

b. Suppose we use the information in this example to provide a preliminary estimate of p. How large a sample would be required to produce an estimate of p that we are 99% confident differs from the true value by at most 0.009?

The margin of error is of:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

A sample of n is required, and n is found for M = 0.009. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.009 = 2.575\sqrt{\frac{0.005*0.995}{n}}$

$0.009\sqrt{n} = 2.575\sqrt{0.005*0.995}$

$\sqrt{n} = \frac{2.575\sqrt{0.005*0.995}}{0.009}$

$(\sqrt{n})^2 = (\frac{2.575\sqrt{0.005*0.995}}{0.009})^2$

$n = 407.3$

Rounding up:

A sample of 408 is required.

c. Suppose we did not have a preliminary estimate of p. How large a sample would be required if we wanted to be at least 99% confident that the sample proportion differs from the true proportion by at most 0.009 regardless of the true value of p?

Since we have no estimate, we use $\pi = 0.5$

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.009 = 2.575\sqrt{\frac{0.5*0.5}{n}}$

$0.009\sqrt{n} = 2.575*0.5$

$\sqrt{n} = \frac{2.575*0.5}{0.009}$

$(\sqrt{n})^2 = (\frac{2.575*0.5}{0.009})^2$

$n = 20464.9$

Rounding up:

A sample of 20465 is required.

8 0

2 years ago

The water in a reservoir decreased by 47% during a drought. Before the drought, the reservoir held 44,580 acre ft (AF) of water.

yawa3891 [41]

Multiply 44580 by .47
that gives you 20952.6 which equals 47% of the water
take the 44580, and subtract the 20952.6
giving you the remainder as your answer
23627.4

6 0

2 years ago