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2 years ago

Adam is going to make concrete

Mathematics

1 answer:

hodyreva [135]2 years ago

5 0

Answer:

90 kg of stone

Step-by-step explanation:

Adam has 8 x 25 = 200

19 x 22.5 = 427.5

20 x 50 = 1000

He has enough cement and sand

He needs 1090 - 1000 = 90 kg of stone

He needs 2 bags of stone

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The speed limit on a road is 60 mph. The actual speeds of cars are measured and found to be normally distributed with a mean val

Vladimir79 [104]

Answer: 8.1%

Step-by-step explanation:

Given : $\mu=63$

$\sigma=5$

Let x be the random variable that represents the actual speeds of cars.

The speed limit on a road is 60 mph.

Using formula , $z=\dfrac{x-\mu}{\sigma}$ , we have for x= 60+10=70

$\dfrac{70-63}{5}=1.4$

Using z-table for right-tailed test value, The probability of cars exceed the speed limit by more than 10 mph will be

$P(x>70)=P(z>1.4)=0.0807567\approx0.081=8.1\%$

Hence, the percentage of cars exceed the speed limit by more than 10 mph is 8.1%.

6 0

2 years ago

On Saturday, Craig rode his bike 5/8 of a mile. On Saturday, he rode his bike 1/2 of a mile. Craig added 5/8+1/2=6/10and plotted

VashaNatasha [74]

* Craig's answer is not reasonable because to add fractions the denominators must be the same.

** Total distance = 5/8 + 1/2 = 5/8 + 4/8 = 9/8 miles

*** Using the line number to prove the answer:
The line number that represents the problem is in the attached figure.
while the distance between 0 and 1 divided to 8 sections
to represent (5/8) count 5 sections from zero ⇒⇒⇒ point (a)
and to represent (1/2) it is the midpoint between 0 and 1 which mean it is 4 sections but it will be counted from point (a) so, adding 4 sections to point (a) the result will be the point (b)
So, counting from 0 to point (b) will give us 9 sections
and while one section represents (1/8)
So the total distance will be 9 * (1/8) = 9/8 which is agree with the result obtained before

3 0

2 years ago

The ratio of the number of miles Kyle drives to the number of hours he is driving is 468 to 9. What is Kyle's rate of speed? A)

mr_godi [17]

Answer:

the answer is 52

Step-by-step explanation:

you have to divide 468 by 9 and should get you too 52

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2 years ago

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Solve x2 - 8x - 9 = 0. Rewrite the equation so that it is of the form x2 + bx = c.

barxatty [35]

Answer:

x=9,-1 and $x^2+(-8)x=9$

Explanation:

we have been given with the quadratic equation $x^2-8x-9$

we compare the given quadratic equation with general quadratic equation

general quadratic is $ax^2+bx+c=0$

from given quadratic equation a=1,b= -8,c= -9

substituting these values in the formula for discriminant $D=b^{2}-4ac$

$D=(-8)^2-4(1)(-9)=100$

Now, to find the value of x

Formula is $x=\frac{-b\pm\sqrt{D}}{2a}$

Now, substituting the values we will get

$x=\frac{-(-8)\pm\sqrt{100}} {2}= \frac{8\pm10}{2}=9,-1$

And rewritting the given equation by shifting 9 to right hand side of the given equation and taking minus inside the bracket so as to convert it in the form of

$x^2+bx=c$

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2 years ago

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Triangle XYZ has vertices X(–1, –1), Y(–2, 1), and Z(1, 2). What is the approximate measure of angle Z?

Molodets [167]

The answer to this question is A. 37.2°

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2 years ago

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