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3 years ago

8

Mark can clean his father's office in 30 minutes. His younger sister Lynn can clean the office in 40 minutes. How long will it t

ake if they come together and clean the office

2 answers:

zhannawk [14.2K]3 years ago

7 0

If they each do half, it will take 35 minutes.

Elan Coil [88]3 years ago

4 0

10 minutes is the answer

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Convert .2 to a fraction

shepuryov [24]

.2 converted to a fraction would be 1/5

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3 years ago

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In triangle ABC, a = 9, c = 5, and angle B = 120°. Find the measure of angle A to the nearest degree. Show your work.

slamgirl [31]

<u>Answer:</u>

Angle A = 39°

<u>Step-by-step explanation:</u>

We are given that there is a triangle ABC where a = 9, c = 5 and angle B = 120° and we are to find the measure of angle A.

But first we need to find the side b using the law of cosine:

$b^2 = a^2 + c^2- 2a*c*cos(120)$

$b^2 = 81 + 25 - 2*9*5*(-0.5)$

$b=\sqrt{151}$

Now finding angle A using law of cosine:

$cos(A) = \frac{b^2+c^2-a^2}{2b*c}$

$cos(A) = \frac{151+25-81}{2*12.29*5}$

$cos A=0.7730$

$A=39.38$

Therefore, the measure of angle A = 39°.

7 0

3 years ago

Read 2 more answers

NASA launches a rocket at t = 0 seconds. Its height, in meters above sea-level, as a function of time is given by h ( t ) = − 4.

Oliga [24]

Answer:

$\displaystyle 1)48.2 \: \: \text{sec}$

$\rm \displaystyle 2)3021.6 \: m$

Step-by-step explanation:

<h3>Question-1:</h3>

so when <u>flash down</u><u> </u>occurs the rocket will be in the ground in other words the elevation(height) from ground level will be 0 therefore,

to figure out the time of flash down we can set h(t) to 0 by doing so we obtain:

$\displaystyle - 4.9 {t}^{2} + 229t + 346 = 0$

to solve the equation can consider the quadratic formula given by

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

so let our a,b and c be -4.9,229 and 346 Thus substitute:

$\rm\displaystyle t = \frac{ - (229) \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

remove parentheses:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ {229}^{2} - 4.( - 4.9)(346)} }{2.( - 4.9)}$

simplify square:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 4( - 4.9)(346)} }{2.( - 4.9)}$

simplify multiplication:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 52441- 6781.6} }{ - 9.8}$

simplify Substraction:

$\rm\displaystyle t = \frac{ - 229 \pm \sqrt{ 45659.4} }{ - 9.8}$

by simplifying we acquire:

$\displaystyle t = 48.2 \: \: \: \text{and} \quad - 1.5$

since time can't be negative

$\displaystyle t = 48.2$

hence,

at <u>4</u><u>8</u><u>.</u><u>2</u><u> </u>seconds splashdown occurs

<h3>Question-2:</h3>

to figure out the maximum height we have to figure out the maximum Time first in that case the following formula can be considered

$\displaystyle x _{ \text{max}} = \frac{ - b}{2a}$

let a and b be -4.9 and 229 respectively thus substitute:

$\displaystyle t _{ \text{max}} = \frac{ - 229}{2( - 4.9)}$

simplify which yields:

$\displaystyle t _{ \text{max}} = 23.4$

now plug in the maximum t to the function:

$\rm \displaystyle h(23.4)- 4.9 {(23.4)}^{2} + 229(23.4)+ 346$

simplify:

$\rm \displaystyle h(23.4) = 3021.6$

hence,

about <u>3</u><u>0</u><u>2</u><u>1</u><u>.</u><u>6</u><u> </u>meters high above sea-level the rocket gets at its peak?

5 0

2 years ago

The admission fee is $1.50 for children and $4.00 for adults. If 2700 people enter and $7800 is collected how many children and

Snowcat [4.5K]

Answer:

1200 children and 1500 Adults

Step-by-step explanation:

Suppose x be the children and y be the adults as total people are 2700 that have entered so we can write an equation as

x+y=2700 (Equation 1)

and as per child $1.50 is the cost and $4 for every adult and collectively we have got $7800 so we can write the equation as

1.50x+4y=7800 (Equation 2)

Extracting the value of y from equation 1

Y=2700-x (Equation 3)

Putting the value of y from equation 3 into equation 2

1.50x+4(2700-x)=7800

1.50x+10800-4x=7800

1.50x-4x=7800-10800

-2.5x=-3000

Cancellation of negative signs on both sides

x=3000/2.5

x=1200

Putting the value of x in equation 3 to get the value of y

y=2700-1200

y=1500

5 0

3 years ago

There are 64 pretzels in a 16-ounce bag of chocolate-covered pretzels.

Shkiper50 [21]

Answer:

64 pretzels in a 16 oz bag

1 oz will contain 64/16 pretzels = 4

5 oz will therefore contain 4 x 5 = 20 pretzels

Step-by-step explanation:

See here for a deeper explanation! ^^

Hopefully it helps :)

brainly.com/question/200543

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3 years ago

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