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kiruha [24]
4 years ago
11

Mary decreaser time in the mile walk from 30 minutes to 24 minutes what is the percent decrease

Mathematics
1 answer:
slega [8]4 years ago
3 0
There was a 20% decrease. To find the decrease, subtract the old number from the new number. (30-24=6) Then divide the decrease (6) by the original number and multiply the answer by 100. (6/30=0.2 0.2*100=20).
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If line d intersects plane F, then how many points on line d also lie on plane F?
Fittoniya [83]
The answer would be 
B) 1
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7 0
3 years ago
Mrs. Hall bought a package of 8 pencils for $4.64. What is the unit price per pencil?
ahrayia [7]

Answer:

$0.58

Step-by-step explanation:

There are 8 pencils per package. To find the value of each pencil, divide the cost by 8

4.64/8 = $0.58

8 0
3 years ago
Read 2 more answers
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
Mileage tests are conducted for a particular model of automobile. If a 98% confidence interval with a margin of error of 1 mile
Llana [10]

Answer: 37

Step-by-step explanation:

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Population standard deviation: \sigma=2.6 miles per gallon.

We know that when the population standard deviation is known then the formula to find the sample size is given by  :

n=(\dfrac{z_{\alpha/2}\times \sigma}{E})^2

n=(\dfrac{(2.33)\times 2.6}{1})^2=36.699364\approx37  [Round to the next whole number.]

Hence, the required number of automobiles should be used in the test = 37

7 0
4 years ago
Which function is equivalent to y = 3(x + 2)2 + 7?
Tems11 [23]

Answer:

The answer is D

Step-by-step explanation:

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7 0
3 years ago
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