Write an equation to represent 'twice a number (x) is fifty"
2 answers:
Hi there,
Your question is "twice a number (x) is fifty"
Recall how a number is represented by x.
Twice a number would be represented as 2x.
Therefore, to represent that twice a number is equal to 50, that would result in the expression:
If you're looking to solve this equation, it's often best to think about the "reverse" of the current equation.
Notice how 2 is multiplying the x.
To isolate x, divide that side by 2.
However, recall that whatever is done to one side of an equation must also be done to the other side of the equation. Therefore, you will need to divide both sides by 2.
Equation:
Solving for x: 25
Hope that helps!
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Answer:
n = 98, that is, she scored at the 98th percentile.
Step-by-step explanation:
When the distribution is normal, we use the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:
She scored 38, so
Test scores are normally distributed with a mean of 25 and a standard deviation of 6.4.
This means that
Find the percentile:
We have to find the pvalue of Z. So
has a pvalue of 0.98(rounding to two decimal places).
So n = 98, that is, she scored at the 98th percentile.