What are the solutions to 5x2 - x-1<0?
2 answers:
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<h3>Answer: 6</h3>
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Explanation:
Rule: If a set has n elements in it, then it will have 2^n subsets.
For example, there are n = 3 elements in the set {a,b,c}. This means there are 2^n = 2^3 = 8 subsets. The eight subsets are listed below.
- {a,b,c} .... any set is a subset of itself
- {a,b}
- {a,c}
- {b,c}
- {a}
- {b}
- {c}
- { } ..... the empty set
Subsets 2 through 4 are subsets with exactly 2 elements. Subsets 5 through 7 are singletons (aka sets with 1 element). The last subset is the empty set which is a subset of any set. You could use the special symbol to indicate the empty set.
For more information, check out concepts relating to the power set.
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The problem is asking what value of n will make 2^n = 64 true.
You could guess-and-check your way to see that 2^n = 64 has the solution n = 6.
Another approach is to follow these steps.
Which is fairly trivial.
Or you can use logarithms to solve for the exponent.
Due to rounding error, we don't land exactly on 6 even though we should.
Answer:
68% of the incomes lie between $36,400 and $38,000.
Step-by-step explanation:
We are given the following information in the question:
Mean, μ = $37,200
Standard Deviation, σ = $800
We are given that the distribution of SAT score is a bell shaped distribution that is a normal distribution.
Empirical rule:
- Almost all the data lies within three standard deviation of mean for a normally distributed data.
- About 68% of data lies within one standard deviation of mean.
- About 95% of data lies within two standard deviation of mean.
- About 99.7% of data lies within three standard deviation of mean.
Thus, 68% of data lies within one standard deviation.
Thus, 68% of the incomes lie between $36,400 and $38,000.