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3 years ago

The level of water in a dam was decreasing by 20% each day. If the level of water was 1500cm,what was the level after two days?

Mathematics

2 answers:

Harlamova29_29 [7]3 years ago

7 0

Answer:

960 cm.

Step-by-step explanation:

For the first day:

Subtract the primary level of water by the 20% of it. 20% of 1500 is:

$0.2*1500=300$ (Convert the percent to decimal)

Then subtract 1500 to 300. That would become 1200cm for the first day.

For the second day:

Subtract the level of water from the first day by 20% of it. 20% of 1200 is:

$0.2*1200= 240$

Then subtract 1200 to 240. That would become 960 for the second day.

The level of the water after 2 days is 960 cm.

nirvana33 [79]3 years ago

5 0

Answer:900

Step-by-step explanation:

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A. Create a set of 5 points that are very close together and record the standard deviation. Next, add a sixth point that is far

defon

Answer: The addition of the new point alters the previous standard deviation greatly

Step-by-step explanation:

Let the initial five points be : 2 3 4 5 and 6. In order to calculate the standard deviation for this data, we will need to calculate the mean first.

Mean = summation of scores/number of scores.

The mean is therefore: (2+3+4+5+6)/5 = 20/5 = 4.

We'll also need the sum of the squares of the deviations of the mean from all the scores.

Since mean = 4, deviation of the mean from the score "2" = score(2) - mean (4)

For score 3, it is -1

For 4, it's 0

For 5 it's 1

For 6 it's 2.

The squares for -2, -1, 0, 1, and 2 respectively will be 4, 1 , 0, 1, 4. Summing them up we have 10 i.e (4+1+0+1+4=10).

Calculating the standard deviation, we apply the formula:

√(summation of (x - deviation of mean)^2)/N

Where N means the number of scores.

The standard deviation = √(10/5) = 1.4142

If we add another score or point that is far away from the original points, say 40, what happens to the standard deviation. Let's calculate to find out.

i.e we now have scores: 2, 3, 4, 5, 6 and 40

We calculate by undergoing same steps.

Firstly mean. The new mean = (2+3+4+5+6+40)/6 = 60/6 = 10.

The mean deviations for the scores : 2, 3, 4, 5, 6 and 40 are -8, -7, -6, -5, -4 and 30 respectively. The squares of these deviations are also 64, 49, 36, 25, 16 and 900 respectively as well. Their sum will then be 1090. i.e. (64+49+36+25+16+900 = 1090).

The new standard deviation is then=

√(1090/6)

= √181.67

= 13.478.

It's clear that the addition of a point that's far away from the original points greatly alters the size of the standard deviation as seen /witnessed in this particular instance where the standard deviation rises from 1.412 to 13.478

7 0

3 years ago

Healthy Gym

ehidna [41]

Answer:

$c=2d+5$

Step-by-step explanation:

Let

d ------> the number of days

c -----> the cost

we know that

The cost is equal to the number of days multiplied by $2 per day plus the initial fee of $5

The linear equation in slope-intercept form is

$c=md+b$

where

m is the slope

b is the c-intercept (value of c when the value of d is equal to zero)

in this problem we have

m=$2 per day

b=$5

substitute

$c=2d+5$

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3 years ago

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vodka [1.7K]

Answer:

the answer is one solution

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3 years ago

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Find the slope of the line that passes through the points A(–3, 1) and B(2, –5).

Kipish [7]

Answer:

- 6/5

Step-by-step explanation:

To find the slope

m = ( y2-y1)/(x2-x1)

= ( -5-1)/(2- -3)

= (-5-1)/(2+3)

- 6/5

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3 years ago

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If the tangent line to y = f(x) at (7, 4) passes through the point (0, 3), find f(7) and f '(7).

jarptica [38.1K]

Hello :
f'(7) = the slope of the tangent line : let A(7,4) B(0,3)
the slope is : (YB - YA)/(XB -XA)= (3-4)/(0-7) = -1/-7 = 1/7=f'(7)
the equation of the tangent line is :
y-3 = 1/7 (x-0)
y = (1/7)x+3
the line tangent and the graph of : f passes through the point A(7, 4)
x= 7 y=4 so : f(7) =4

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3 years ago