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zloy xaker [14]
3 years ago
15

8. Number of boys in a class is twice the number of girls. 20% of the girls are brunettes and of the rest – half are blondes: Ma

ry, Clara, Gina and Trisha. How many boys study in this class?
Mathematics
1 answer:
slega [8]3 years ago
8 0

Answer:

<em>20 boys </em>

Step-by-step explanation:

b = 2g

100% - 20% = 80%

80% ÷ 2 = 40% = 0.4

0.4g = 4 ⇒ g = 4 ÷ 0.4 = 10

b = 2 × 10 = 20

There are 10girls and <em>20 boys</em> study in the class.

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LUCKY_DIMON [66]

10x10x10x10x10

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6 0
3 years ago
For what x-value(s) does cos(x) = 1?<br><br> -360°<br><br> 0°<br><br> 360°<br><br> all of the above
dlinn [17]
Cos(x) = 1 at 0 and 2pi 360 and -360 is the same angle as 2pi so all of the above if you start at 0 and make a complete circle (360) you will be back at point 0.

7 0
3 years ago
alex is running in a clockwise direction around a circular track with radius 60 yards. he runs for 20 minutes at a speed of 4 ya
Ganezh [65]

Answer:

  100.9 yards

Step-by-step explanation:

One circuit of the track is a distance of ...

  C = 2πr = 2π(60 yd) = 120π yd.

At Alex's running rate, the distance covered in 20 minutes is ...

  (4 yd/s)(20 min)(60 s/min) = 4800 yd

The number of circuits will be ...

  (4800 yd)/(120π yd/circuit) = 40/π circuits ≈ 12.7324 circuits

The last of Alex's laps is more than half-completed, so the shortest distance to his starting point is 13 -12.7324 = 0.2676 circuits,

That distance is (0.2676 circuits)×(120π yd/circuit) ≈ 100.88 yd

The shortest distance along the track to Alex's starting point is about 100.9 yards.

_____

<em>Additional comment</em>

The exact distance is 120(13π-40) yards. The distance will vary according to your approximation for pi. If you use 3.14, this is about 98.4 yards.

3 0
3 years ago
PLEASE HELP WILL MARK BRAINLIEST!!
Arturiano [62]

Answer:

Yes.

Step-by-step explanation:

Though x and y can be achieved in a system of equations. The equation

x (t)=0.0411905(t^2)+(-0.164619)t+28.0114

And

y (t)=-0.024127(t^2)+(-0.591143)t+(-87.4403)

Are not system of equations but rather two different models of equations. Nevertheless

To find t in the first equation, x(t) has to be equal to zero.

When the t is substituted in the second equation, t will completely disappear. Given the value of y(t) and vice versa.

7 0
3 years ago
5 less than 3 times a number is 7. How would I write this as an equation
sladkih [1.3K]
You want to break this down.

“5 less than” means you’ll subtract 5 from something.

That something is “3 times a number.” “3 times a number” means 3•x or 3x, since we’ll use x for that unknown number.

So, “5 less than 3 times a number” means “subtract 5 from 3x”: 3x-5

“Is” means “equals”. So 3x-5= something.

7, well, that’s 7.

So “5 less than 3 times a number is 7” means ”subtract 5 from 3x and set that equal to 7.”

3x-5=7
5 0
3 years ago
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