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3 years ago

There are 12 more boys than girls at a school play. The ratio of boys to girls is 7:5. How many students were there altogether

Mathematics

1 answer:

taurus [48]3 years ago

7 0

12 more boys than girls

ratio of boys to girls = 7:5

thus 2/12 is difference between boys and girls = 12

total students = 12 ÷ 2/12 = 72

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What is the sum of 20x^2-10x-30

ivann1987 [24]

Answer:

The sum of the roots is 0.5

Step-by-step explanation:

The correct question is

What is the sum of the roots of 20x^2-10x-30

we know that

In a quadratic equation of the form

$ax^{2} +bx+c=0$

The sum of the roots is equal to

$-\frac{b} {a}$

in this problem we have

$20x^{2} -10x-30=0$

$a=20\\b=-10\\c=-30$

substitute

$-\frac{(-10)} {20}=0.5$

Verify

Find the roots of the quadratic equation

The formula to solve a quadratic equation is equal to

$x=\frac{-b\pm\sqrt{b^{2}-4ac}} {2a}$

$a=20\\b=-10\\c=-30$

substitute

$x=\frac{-(-10)\pm\sqrt{-10^{2}-4(20)(-30)}} {2(20)}$

$x=\frac{10\pm\sqrt{2,500}} {40}$

$x=\frac{10\pm50} {40}$

$x=\frac{10+50} {40}=1.5$

$x=\frac{10-50} {40}=-1$

The roots are x=-1 and x=1.5

The sum of the roots are

$-1+1.5=0.5$ ----> is ok

5 0

3 years ago

The $25.00 shirt costs the store $20.00. Find the markup rate.

pochemuha

Answer:

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Step-by-step explanation:

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3 years ago

Can I get some help with proofs? Picture is attached

aleksandr82 [10.1K]

Give a reason for each step of the proof.

Given: <1 and <2 are complimentary

<1 is congruent to <3,

<2 is congruent to <4

Prove: <3 and <4 are complimentary

Statements: Reasons:

1. <1 and <2 are complimentary 1.Given

2. m<1 + m<2=90* 2.DEFINITION OF COMPLEMENTARY ANGLES

3. <1 is congruent to <3, <2 is congruent to <4 3.__GIVEN______

4. m<1=m<3, m<2=m<4 4.DEFINITION OF CONGRUENT ANGLES_

5. m<3 + m<2=90* 5. SUBSTITUTION PROPERTY (m<1 is replaced by m<3.)

6. m<3 +m<4=90* 6. DEFINITION OF COMPLEMENTARY ANGLES

7. <3 and <4 are complimentary 7. DEFINITION OF COMPLEMENTARY ANGLES

8 0

3 years ago

This is confusing i need help ;-;

katovenus [111]

Answer:

B I think

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

A circular plate has circumference 16.3 inches. What is the area of this plate? Use 3.14 for pi.

serg [7]

Answer:

C = 2πr = 16.3

2(3.14)r = 16.3

r = 16.3/6.28

r = 2.5955414

Area: A = πr2

A = 3.14(2.5955414)2

A = 21.15366242 $in^{2}$

Step-by-step explanation:

The answer would be 21.2 $in^{2}$

6 0

3 years ago