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3 years ago

The ratio of boys and girls in the school

Mathematics

2 answers:

erma4kov [3.2K]3 years ago

7 0

Answer:

45 students

Step-by-step explanation:

to make sure there are 20 boys you need to multiply 4 by 5

so multiply the 5 by 5 as well

then add what you get!!

Elanso [62]3 years ago

6 0

Answer:

Step-by-step explanation:

20 boys= 5 times the ratio

So, 5x5=25

25 girls and 20 boys= 45 students

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Perform the indicated operations. Write the answer in standard form, a+bi.<br> (5 + 6i)(5 - 6i)

lubasha [3.4K]

$\boxed{\underline{\bf \: ANSWER}}$

$\sf \: ( 5 + 6 i ) ( 5 - 6 i )$

Multiply complex numbers 5+6i and 5-6i in the same way as you multiply binomials.

$\dashrightarrow \sf 5\times 5+5\times \left(-6i\right)+6i\times 5+6\left(-6\right)i^{2}$

By definition, i² is -1.

$\dashrightarrow \sf 5\times 5+5\times \left(-6i\right)+6i\times 5+6\left(-6\right)\left(-1\right)$

Do the multiplications.

$\dashrightarrow \sf \: 25-30i+30i+36$

Now cancel -30i & +30i

$\dashrightarrow \sf \: 25 \: \bcancel{- 30i} \: + \: \bcancel{30i}+36$

Now the equation becomes

$\dashrightarrow \sf \: 25 \: + 36 \\ \dashrightarrow \boxed{\bf \: 61}$

________

Hope it helps.

ŕάίήвόώşάĻţ2²2²

5 0

3 years ago

Read 2 more answers

Given the equation 5x − 4 = –2(3x + 2), solve for the variable. Explain each step and justify your process.

blagie [28]

A.
$5x-4=-2(3x+2) \ \ \ \ \ \ \ \ \ |\hbox{expand the bracket} \\
5x-4=-2 \times 3x-2 \times 2 \\
5x-4=-6x-4 \ \ \ \ \ \ \ \ \ \ \ \ \ |\hbox{add 6x to both sides} \\
11x-4=-4 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\hbox{add 4 to both sides} \\
11x=0 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\hbox{divide both sides by 11} \\
x=0$

B.
$3(2x-4)=5x-1 \\
6x-12=5x-1 \\
\boxed{11x-12=-1} \Leftarrow \hbox{the first mistake} \\
11x=11 \\
\boxed{x=11} \Leftarrow \hbox{the second mistake}$

Megan's solution isn't correct.
The first mistake: she subtracted 5x from the right-hand side of the equation, but added 5x to the left-hand side.
The second mistake: she divided the right-hand side of the equation by 11, but didn't divide the left-hand side.

The correct solution:
$3(2x-4)=5x-1 \ \ \ \ \ \ \ \ \ \ \ |\hbox{expand the bracket} \\
3 \times 2x+3 \times (-4)=5x-1 \\ 6x-12=5x-1 \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\hbox{subtract 5x from both sides} \\
x-12=-1 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\hbox{add 12 to both sides} \\
x=11$

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a musician increases the wavelength of the sound waves she produces without changing their speed. What must be happening to thei

Ilya [14]

Longer wavelength means lower frequency (lower pitch)

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3 years ago

Consider a sphere with a volume of 36,000 π cubic centimeters.

leva [86]

Answer:

30 cm

Step-by-step explanation:

$Vol. of a sphere (4/3) \pi r^3=36000 \pi \\r^3=36000*3/4=27000\\r=30 cm\\$

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3 years ago

A.3/5<br> B.2/3<br> C.5/3<br> D.2

lozanna [386]

Answer:

The answer was d

Step-by-step explanation:

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