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Anna35 [415]
3 years ago
9

a jogger ran 3 miles due east of his house. then he ran 5 miles at a heading of 30 east of north. how far is he from his house a

fter running 8 miles?
Mathematics
1 answer:
Jobisdone [24]3 years ago
5 0
Let's say her speed was x miles/hour during the first 3 miles runThen, time = distance/speedt1 = 3/x       eq1 In the next 4 miles run, her speed = x-1 miles/hourTime taken:t2 = 4/(x-1)      eq2 Now, total time:t1 + t2 = 1 3/5 hourssubstitute t1 and t2 from eqs. 1 and 2 3/x + 4/(x-1) = 1 3/5=> 3/x + 4/(x-1) = 8/5
=> 3(x-1) + 4x = 8x(x-1)/5=> 35x - 15 = 8x2 - 8x=> 8x2 - 43x + 15 = 0=> (8x-3)*(x-5) = 0=> x = 3/8 or 5 miles/hourx can not be 3/8 miles/hour because in that case, the speed during 4 miles run would be 3/8-1 = negative numberi.e. speed during 3 miles segment = 5 miles/hourand speed during 4 miles segment = 5-1 = 4 miles/hour
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5
Romashka [77]

9.42 Units

Step-by-step explanation:

Since the angle shown is 90 degrees we can deduce that the rest of the arc is 270 degrees therefore we can make the fraction:

270/360; 360 being the total angle measurement of a circle

270/360 simplifies to 3/4

The fraction represents how much of the circle that arc covers

Now we have to find the circumference which would be

2(3.14)r

r = 2 therefore: 2(3.14)2 = 12.56

Now that we have the circumference of the WHOLE circle we multiply it by 3/4 to find out the arc length

Which gives us  9.42

8 0
3 years ago
Danielle and David each have a job. Danielle earns $15 an hour. She also receives a $50 weekly bonus. Danielle wrote an equation
S_A_V [24]
For starters, create an equation to show David's earnings. We can do this using Danielle's as a basis, which is set up as y=(# of hours)x+(bonus). This gives us y=12x+80. Now, as we need both their ys to be equal, we just set both equations equal to each other, making 15x+50=12x+80. Now, we solve for x, starting with 15x+50=12x+80, subtracting 12x from both sides to get 3x+50=80, subtracting 50 from both sides to get 3x=30, and dividing three from both sides to get x=10. To check, we just plug in our answer to both equations and see if the ys match up. With Danielle's equation, we get y=15(10)+50=150+50=200 and with David's equation, we get y=12(10)+80=120+80=200, proving that our answer is correct.
5 0
3 years ago
Read 2 more answers
A bird sees a worm on the ground 50 m. below. The bird dives for the worm at a speed of 6 m/sec. The function h\left( t \right)
iragen [17]

<u>Given</u>:

The height of the bird at time t is given by the function h(t)=-4.9t^2+6t+50

We need to determine the time it takes the worm to be eaten by the bird.

<u>Time taken:</u>

The time can be determined by substituting h(t) = 0 in the function.

Thus, we have;

0=-4.9t^2+6t+50

Switch sides, we get;

-4.9t^2+6t+50=0

Let us solve the equation using the quadratic formula.

Thus, we get;

t=\frac{-6 \pm \sqrt{6^{2}-4(-4.9) 50}}{2(-4.9)}

Simplifying, we get;

t=\frac{-6 \pm \sqrt{36+980}}{-9.8}

t=\frac{-6 \pm \sqrt{1016}}{-9.8}

t=\frac{-6 \pm 31.87}{-9.8}

The values of t are given by

t=\frac{-6 + 31.87}{-9.8}   and   t=\frac{-6 - 31.87}{-9.8}

t=\frac{25.87}{-9.8}    and   t=\frac{-37.87}{-9.8}

t=-2.4    and   t=3.9

Since, the value of t cannot be negative, then t=3.9

Thus, the time taken by the bird to eat the worm is t=3.9 seconds.

Hence, Option B is the correct answer.

5 0
3 years ago
The point is plotted on the number line.What whole number best approximates the value of x?
sattari [20]

You can eliminate 81 because we know \sqrt{81} =9

The dot is on approximately 9.32 (my estimate) so I would square that number:

(9.32)² = 86.8624 so if you round this you get 87

6 0
3 years ago
Read 2 more answers
X = y - 3
Leviafan [203]
The answer is A. (1, 4), because when the values are substituted in to the equations, you get 1 = 4 - 3 and 1 + 12 = 13, which are both correct. I hope this helps!
3 0
3 years ago
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