Answer:
4 hours
Step-by-step explanation:
The general formula for distance, rate and time is:
d = rt, where distance is the product of rate multiplied by time
Given that one train is moving at a rate of 70 mph and one is moving at a rate of 62 mph in the opposite direction, the combined distance over time is equal to 528 miles. Using the variable 't' for time:
70t + 62t = 528
Combine like terms: 132t = 528
Divide both sides by 132: 132t/132 = 528/132 or t = 4 hours
Answer:
x = - 1, x = - 11
Step-by-step explanation:
Given
2| x + 6 | - 4 = 6 ( add 4 to both sides )
2|x + 6 | = 10 ( divide both sides by 2 )
| x + 6 | = 5
The absolute value function always gives a positive result, but the expression inside can be positive or negative, that is
x + 6 = 5 or - (x + 6) = 5
solve both
x + 6 = 5 ( subtract 6 from both sides )
x = - 1
or
- (x + 6) = 5 , that is
- x - 6 = 5 ( add 6 to both sides )
- x = 11 ( multiply both sides by - 1 )
x = - 11
Answer:
The 90% confidence interval for the mean test score is between 77.29 and 85.71.
Step-by-step explanation:
We have the standard deviation for the sample, so we use the t-distribution to solve this question.
The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So
df = 25 - 1 = 24
90% confidence interval
Now, we have to find a value of T, which is found looking at the t table, with 24 degrees of freedom(y-axis) and a confidence level of 
. So we have T = 2.064
The margin of error is:
In which s is the standard deviation of the sample and n is the size of the sample.
The lower end of the interval is the sample mean subtracted by M. So it is 81.5 - 4.21 = 77.29
The upper end of the interval is the sample mean added to M. So it is 81.5 + 4.21 = 85.71.
The 90% confidence interval for the mean test score is between 77.29 and 85.71.
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When factoring, it's easier to "pick out" the GCF first because it makes it simpler to factor even further. Otherwise, you will be troubled with lots of numbers and variables, so it will just get confusing.
