Answer:
1300
Step-by-step explanation:
Let the amount put in the station's tank = x
4(400 + x) = 8100 - x Remove the brackets
1600 + 4x = 8100 - x Subtract 1600 from both sides
1600 - 1600 + 4x = 8100 - 1600 - x Do the subtraction
4x = 6500 - x Add x to both sides
4x + x = 6500 - x + x
5x = 6500 Divide by 5
5x/5 = 6500/5
x = 1300
1300 gallons were added to the station's tank.
Answer:
The correct option is;
A. A set of nine data pairs with a correlation coefficient r = -0.4
Step-by-step explanation:
In statistical analysis, it is important to make use of an adequate sample size in order to arrive at a valid result. An analysis with a very small sample size can provide misleading results
When performing regression analysis it is generally accepted by researchers that each variable should have at least 10 observations.
Therefore, the data set having nine data pairs with a negative correlation of -0.4 will provide the most valid result that can then be used for generalization about the larger statistical population.
Answer:
<h3><em>
D. 880 = 45d + 70; 18 days.</em></h3>
Step-by-step explanation:
We are given fixed monthly charge = $70.
The cost of preschool per day = $45.
Number of days = d.
Total cost of d days = cost per day × number of days + fixed monthly charge.
Therefore, we get equation
880 = 45×d+70
<h3>880 = 45d +70.</h3>
Now, we need to solve the equation for d.
Subtracting 70 from both sides, we get
880-70 = 45d +70-70
810=45d
Dividing both sides by 45, we get

18=d.
Therefore,<em> 18 days Barry attended preschool last month.</em>
<em>Therefore, correct option is D option.</em>
<h3><em>
D. 880 = 45d + 70; 18 days.</em></h3>