Simplify the expression: 4(x + 3) = 40
2 answers:
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Answer:
C. y +3 = x +3
Step-by-step explanation:
We need to find in below option x has direct variation with y.
We solve for each;
A.
From above equation we can state that 2 times y is equal to 7 less than 3 times of x.
Hence it doesn't represent direct variation.
B.
Solving above expression we get;
From above equation we can state that y is equal to 10 more than x.
Hence it doesn't represent direct variation.
C.
Solving above expression we get;
From above equation we can state that y is equal to x.
Hence it represent direct variation.
D.
Solving above expression we get;
From above equation we can state that 4 times y is equal to 2 less than 4 times of x.
Hence it doesn't represent direct variation.
Hence the Answer which represent direct variation of x and y is,
C.
Answer:
Step-by-step explanation:
Given that a researcher is trying to decide how many people to survey.
We have confidence intervals are intervals with middle value as the mean and on either side margin of error.
Confidence interval = Mean ± Margin of error
Thus confidence interval width depends on margin of error.
Margin of error =
Thus for the same confidence level and std deviation we find margin of error is inversely proportional to square root of sample size.
Hence for small n we get wide intervals.
So if sample size = 300, the researcher will get wider confidence interval