Please help! This is my brother’s question (4th grade)
1 answer:
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Answer:
At least 547 records need to be studied.
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of , and a confidence interval
, we have the following confidence interval of proportions.
In which
Z is the zscore that has a pvalue of .
And the margin of error is:
95% confidence interval
So , z is the value of Z that has a pvalue of
, so
.
In this problem, we have that:
At least 547 records need to be studied.
Answer:
The numerical length of RS is 22 units
Step-by-step explanation:
∵ Point S is on the line segment RT
→ <em>That means S divide RT into two parts RS and ST</em>
∴ RS + ST = RT
∵ RS = 4x - 10
∵ ST = 2x - 10
∵ RT = 4x - 4
→ <em>Substitute them in the statement above</em>
∴ 4x - 10 + 2x - 10 = 4x - 4
→ <em>Add the like terms in the left side</em>
∴ (4x + 2x) + (-10 + -10) = 4x - 4
∴ 6x + (-20) = 4x - 4
∴ 6x - 20 = 4x - 4
→ <em>Add 20 to both sides</em>
∴ 6x -20 + 20 = 4x - 4 + 20
∴ 6x = 4x + 16
→ <em>Subtract 4x from both sides</em>
∴ 6x - 4x = 4x - 4x + 16
∴ 2x = 16
→ <em>Divide both sides by 2 to find x</em>
∴
∴ x = 8
→ <em>Substitute the value of x in Rs to find its length</em>
∵ RS = 4(8) - 10
∴ RS = 32 - 10
∴ RS = 22 units
The numerical length of RS is 22 units