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2 years ago

3. 40% of x is 35. Write an equation. Then use your equation to find x.

Mathematics

2 answers:

ivann1987 [24]2 years ago

7 0

Answer:

87.5

Step-by-step explanation:

40% of x = 35 , that is

$\frac{40}{100}$ x = 35

0.4x = 35 ( divide both sides by 0.4 )

x = $\frac{35}{0.4}$ = 87.5

MrRissso [65]2 years ago

5 0

Answer: x = 87.5

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What is the probability of flipping a coin 10 times and getting tails 7 times ? Round your answer to the nearest tenth of a perc

KatRina [158]

Answer:

Option C: 11.7%

Step-by-step explanation:

The number of elements in sample space when a coin is flipped 10 times will be:

$n(S) = 2^{10} \\= 1024$

Let A be the event that the tails appear 7 times:

Then,

$C_{(n,k)}=\frac{n!}{(k!)(n-k)!} \\where\\n=population\\k=picks\\In our case, k =7\\and\\n=10\\C_{(10,7)}= \frac{10!}{(7!)(10-3)!}\\= 120\\So, \\P(A) = \frac{n(A)}{n(S)} \\P(A) = \frac{120}{1024} \\= 0.1171\\$

Converting into percentage:

$P(A) = 0.1171*100=11.7%$

So, option C is correct ..

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3 years ago

Solve the system of linear equations by substituting. Check your solution

Ghella [55]

QUESTION 4

The given system of linear equations are,

$y = 5x - 7...(1)$

and

$- 3x - 2y = - 12...(2)$

We put equation (1) into equation (2) to obtain,

$- 3x - 2(5x - 7) = - 12$

We expand to get,

$- 3x - 10x + 14 = - 12$

Group like terms to get,

$- 3x - 10x = - 12 - 14$

Simplify to get,

$- 13x = - 26$

Divide both sides by -13 to get,

$x = 2$

Put the value of x into equation (1) to get,

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The solution is

$x = 2 \: \: and \: \: = 3$

QUESTION 5

The given system of linear equations are

$-4x+y=6....(1)$
and

$-5x-y=21...(2)$

We make y the subject in equation (1) to get,

$y = 4x + 6....(3)$

Put equation (3) into equation (2) to get,

$- 5x - (4x + 6) = 21$

We expand to get,

$- 5x - 4x - 6 =21$

We group like terms to get,

$- 5x - 4x = 21 + 6$

This implies that,

$- 9x = 27$

We divide both sides by -9 to get,

$x = - 3$

Put the value of x in to equation 3 to get,

$y = 4( - 3) + 6$

$y = - 12 + 6 = - 6$

Therefore the solution is

$x = - 3 \: and \: y = - 6$

QUESTION 6

The given equations are,

$-7x-2y=-13...(1)$

and

$x-2y=-13...(2)$

Make x the subject in equation (2) to get,

$x = 2y - 13...(3)$

Put equation (3) into equation (1) to get,
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$- 14y + 91 - 2y = - 13$

We group like terms to obtain,

$- 14y - 2y = - 13 - 91$

.Simplify to get,

$- 16y = - 104$

Divide through by -16 to get,

$y = \frac{13}{2}$

Put the value of y into equation (3) to get,

$x = 2( \frac{13}{2} ) - 13$

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3 years ago

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Tpy6a [65]

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Eva8 [605]

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Step-by-step explanation:

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3 years ago

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3 years ago

3. 40% of x is 35. Write an equation. Then use your equation to find x.​

3. 40% of x is 35. Write an equation. Then use your equation to find x.