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Sedaia [141]
3 years ago
7

Andrew has 30 rocks. He has 10 more rocks then Amanda. He has 15 fewer rocks then Rob. How many rocks does each person have?

Mathematics
1 answer:
Elena-2011 [213]3 years ago
3 0

Answer:

Amanda has 20, Rob has 45

Step-by-step explanation:

Amanda has ten fewer rocks than Andrew, 30-10=20

Rob has 15 more rocks than Andrew, 30+15=45

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FINDDD VALUE OF Y!!!!
solmaris [256]

Answer:

The sum of the internal ángles = 360°

(3y+40)°  and  (3x-70°) are suplementary angles = 180°

then:

(3x-70) + (3y+40) + 120 + x = 360     ⇒ first eq.

(3y+40) + (3x-70) = 180      ⇒  second eq

development:

from the first eq.

3x + x + 3y  =  360  + 70 - 40 - 120

4x + 3y = 430 - 160

4x + 3y = 270       ⇒  third eq.

3y = 270 - 4x

y = (270 - 4x) / 3    ⇒  fourth eq.

from the secon eq.:

3y + 3x = 180 + 70 - 40

3y + 3x = 250 - 40

3y + 3x = 210    ⇒  fifth eq.

multiply by -1  the fifth eq and sum with the third eq.

  -3y  - 3x = -210    ⇒   (fifth eq. *-1)

   3y  + 4x = 270

⇒  0   +  x  = 60

x = 60°

from the fourth eq.

y = (270-4x)/3

y = (270-(4*60)) / 3

y = (270 - 240) / 3

y = 30/3

y = 10°

Probe:

from the first eq.

(3x-70) + (3y+40) + 120 + x = 360

3*60 - 70 + 3*10 + 40 + 120 + 60 = 360

180 - 70 + 30 + 40 + 120 + 60 = 360

180 + 30 + 40 + 120 + 60 - 70 = 360

430 - 70 = 360

Answer:

y = 10

7 0
3 years ago
The function f(x) is shown in the graph.
Semmy [17]

Answer: Logarithmic

Explanation:

This curve is a reflection of the exponential curve over the line y = x, to show that it is the inverse of exponentials. We use logs to help isolate the exponent among other useful properties.

6 0
2 years ago
How long does it take him to make $375.25
frez [133]
Where’s the root to the question
4 0
2 years ago
Suppose a tank contains 400 gallons of salt water. If pure water flows into the tank at the rate of 7 gallons per minute and the
Strike441 [17]

Answer:

Step-by-step explanation:

This is a differential equation problem most easily solved with an exponential decay equation of the form

y=Ce^{kt}. We know that the initial amount of salt in the tank is 28 pounds, so

C = 28. Now we just need to find k.

The concentration of salt changes as the pure water flows in and the salt water flows out. So the change in concentration, where y is the concentration of salt in the tank, is \frac{dy}{dt}. Thus, the change in the concentration of salt is found in

\frac{dy}{dt}= inflow of salt - outflow of salt

Pure water, what is flowing into the tank, has no salt in it at all; and since we don't know how much salt is leaving (our unknown, basically), the outflow at 3 gal/min is 3 times the amount of salt leaving out of the 400 gallons of salt water at time t:

3(\frac{y}{400})

Therefore,

\frac{dy}{dt}=0-3(\frac{y}{400}) or just

\frac{dy}{dt}=-\frac{3y}{400} and in terms of time,

-\frac{3t}{400}

Thus, our equation is

y=28e^{-\frac{3t}{400} and filling in 16 for the number of minutes in t:

y = 24.834 pounds of salt

6 0
3 years ago
2.What is the value of y?<br> 60°<br> 4<br> 30<br> A 3/5<br> 415<br> B4<br> D 8
Dimas [21]

Answer:

i dont know sorry

Step-by-step explanation: cant explain it

8 0
3 years ago
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