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2 years ago

15

a student answers 75% of the questions on a math exam correctly. if he answers 30 questions correctly. how many questions are on

the exam?

1 answer:

Komok [63]2 years ago

8 0

There is 40 questions on the exam

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Helppppppppppppppppppppppppppppppppp

liq [111]

Answer:

The answer is B

you should still invest in a calculator (:

4 0

2 years ago

The object on the right is made from a square-based pyramid joined to a cuboid.

spayn [35]

Answer:

Density of steel = 80.73 gm/ $cm^3$

Step-by-step explanation:

The figure is made up of cuboid and square pyramid.

Height of cuboid, h = 9 cm

Length of cuboid, l = 6 cm

Width of cuboid, w = 6 cm

Volume of cuboid is given by the formula:

$V_{Cuboid} = l \times w \times h$

$V_{Cuboid} = 6 \times 6 \times 9\\\Rightarrow V_{Cuboid} = 324\ cm^3$

Density of Wood , $D_{Cuboid}$ = 0.68g/ $cm^3$

We know that formula of Density is:

$Density = \dfrac{Weight}{Volume}$

$D_{Cuboid} = \dfrac{W_{Cuboid}}{V_{Cuboid}}\\\Rightarrow W_{Cuboid} = V_{Cuboid} \times D_{Cuboid}$

Putting the values:

$W_{Cuboid} = 324 \times 0.68 = 220.32\ gm$

Total weight = $W_{Cuboid} + W_{Pyramid}$

970 = 220.32 $+ W_{Pyramid}$

$W_{Pyramid}$ = 749.68 gm

Volume of pyramid is given as:

$V_{Pyramid}= \dfrac{1}{3} \times \text{Area of Base} \times \text{Vertical Height}$

Base is a square with side 6 cm

$V_{Pyramid}= \dfrac{1}{3} \times 6 \times 6 \times (17 -9)\\V_{Pyramid}= 96\ cm^3$

Density of Steel/Pyramid:

$D_{Pyramid} = \dfrac{W_{Pyramid}}{V_{Pyramid}}\\\Rightarrow D_{Pyramid} = \dfrac{749.68}{96}\\\Rightarrow D_{Pyramid} = 80.73\ gm/cm^3$

5 0

3 years ago

Find the values<br>using<br>expansion formula<br>1) 1.5×2.5

PolarNik [594]

Answer:

$3.75$

Step-by-step explanation:

$1.5 \times2. 5 \\ = 3.75$

Please can I have the brainliest?

Have a nice day!

3 0

2 years ago

Find the solution of the initial value problem<br><br> dy/dx=(-2x+y)^2-7 ,y(0)=0

Leokris [45]

Substitute $v(x)=-2x+y(x)$ , so that $\dfrac{\mathrm dv}{\mathrm dx}=-2+\dfrac{\mathrm dy}{\mathrm dx}$ . Then the ODE is equivalent to

$\dfrac{\mathrm dv}{\mathrm dx}+2=v^2-7$

which is separable as

$\dfrac{\mathrm dv}{v^2-9}=\mathrm dx$

Split the left side into partial fractions,

$\dfrac1{v^2-9}=\dfrac16\left(\dfrac1{v-3}-\dfrac1{v+3}\right)$

so that integrating both sides is trivial and we get

$\dfrac{\ln|v-3|-\ln|v+3|}6=x+C$

$\ln\left|\dfrac{v-3}{v+3}\right|=6x+C$

$\dfrac{v-3}{v+3}=Ce^{6x}$

$\dfrac{v+3-6}{v+3}=1-\dfrac6{v+3}=Ce^{6x}$

$\dfrac6{v+3}=1-Ce^{6x}$

$v=\dfrac6{1-Ce^{6x}}-3$

$-2x+y=\dfrac6{1-Ce^{6x}}-3$

$y=2x+\dfrac6{1-Ce^{6x}}-3$

Given the initial condition $y(0)=0$ , we find

$0=\dfrac6{1-C}-3\implies C=-1$

so that the ODE has the particular solution,

$\boxed{y=2x+\dfrac6{1+e^{6x}}-3}$

5 0

3 years ago

What is the rule if the input is 17 18 _28 40 and the output numbers are 57 56 54_ 34

Mama L [17]

Your answer would be.........................................
A function is when one variable or term depends on another according to a rule. There is a special relationship between the two variables of the function where each value in the input applies to only one value in the output. These rules are called function rules<span>, because they explain how the function operates.

</span>

7 0

3 years ago

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