7√7
using the ' rule of radicals '
• √a × √b ⇔ √ab
simplifying the radicals
√28 = √(4 × 7 ) = √4 × √7 = 2√7
√63 = √(9 × 7) =√9 × √7 = 3√7
√112 = √(16 × 7 ) = √16 × √7 = 4√7
substituting into the expression
3(2√7) - 5(3√7) + 4(4√7) = 6√7 - 15√7 + 16√7 = 7√7
Answer:
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
Step-by-step explanation:
Problems of normally distributed samples are solved using 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 problem, we have that:

What is the probability that a randomly selected exam will require more than 15 minutes to grade
This is 1 subtracted by the pvalue of Z when X = 15. So



has a pvalue of 0.3783.
1 - 0.3783 = 0.6217
62.17% probability that a randomly selected exam will require more than 15 minutes to grade
Lamar used 80% of his data, so he used a greater percentage.
If you're asking how, here's an example
A standard form equation is when it is set up.
Ax + By = C.
6x + 2y = 4.
A slope-intercept form equation is when it is set up y=mx+b.
Y = - 3x + 2.
4y = -8x + 16 then divide all by 4.
y = -2x + 4 slope form.