Answer:
See below
Step-by-step explanation:
Do you mean -12(x+5)=-10?
Divide both sides by -12 -> x+5=10/12
Subtract 5 on both sides -> x=10/12-5 -> x=-4 1/6
So x=-4 1/6
Let me know if this wasn't the right equation
About 400 zebras live at the game reserve.
The proportion would be
30/150 = 80/x
This is because 30 zebras are tagged out of 150 in one area. We know that they tagged 80 total zebras out of x total zebras.
To solve this, cross multiply:
x*30 = 150*80
30x = 12000
Divide both sides by 30:
30x/30 = 12000/30
x = 400
Answer:
About 0.642
Step-by-step explanation:
The phrasing "nine times out of ten" means 9/10 = 0.90 = 90% is the confidence level. We're confident 90% of the time that the confidence interval captures the population parameter we're after (in this case mu = population mean)
The portion "have an average score within 5% of 75%" means that 75% = 0.75 is the center of the confidence interval, and it goes as low as 0.75 - 0.05 = 0.70 and as high as 0.75 + 0.05 = 0.80
This confidence interval is from 70% to 80%, meaning that nine times out of ten, we're confident that the average score is between 70% and 80%
We write the confidence interval as (0.70, 0.80). It's common to use the notation (L, U) to indicate the lower (L) and upper (U) boundaries. You might see the notation in the form L < mu < U. If so, then it would be 0.70 < mu < 0.80; either way they mean the same thing.
The margin of error is 0.05 as its the 5% radius of the interval. It tells us how far the most distant score is from the center (75%)
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In summary, we have these answers
- confidence level = 90%
- margin of error = 5% = 0.05
- confidence interval = (0.70, 0.80)
- interpretation = We're 90% confident that the average exam score is between 0.70 and 0.80
Answer:
The graph of a compound inequality with an "and" represents the intersection of the graph of the inequalities. A number is a solution to the compound inequality if the number is a solution to both inequalities. It can either be written as x > -1 and x < 2 or as -1 < x < 2.