Solve the equation. Check the solution. 8- 2x - 5- 13x = 6
1 answer:
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X miles per hour - <span> speed of the boat in still water
(x - 2) - speed up the river
(x + 2) - speed down the river
</span>
= 
30 * (x + 2) = 38 * (x - 2)
30x + 60 = 38x - 76
- 8x = - 136
x = 17 miles per hour - <span>the speed of the boat in still water.</span>
(x - 2) - speed up the river
(x + 2) - speed down the river
</span>
30 * (x + 2) = 38 * (x - 2)
30x + 60 = 38x - 76
- 8x = - 136
x = 17 miles per hour - <span>the speed of the boat in still water.</span>
Answer:
61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.
Step-by-step explanation:
Given : We want 95% confidence that the sample mean is within 3 minutes of the population mean, and the population standard deviation is known to be 12 minutes.
To find : How many commuters must be randomly selected to estimate the mean driving time of Chicago commuters?
Solution :
At 95% confidence the z-value is z=1.96
The sample mean is within 3 minutes of the population mean i.e. margin of error is E=3 minutes
The population standard deviation is s=12 minutes
n is the number of sample
The formula of margin of error is given by,
Substitute the value in the formula,
Squaring both side,
Therefore, 61 commuters must be randomly selected to estimate the mean driving time of Chicago commuters.