The grades on the last history exam had a mean of 80%. assume the population of grades on history exams is known to be distributed normally, with a standard deviation of 5%. approximately what percent of students earn a score between 70% and 80%?

To calculate for the percent of students who earned scores of 70% and 80%, we compute for the z-scores first and translate the answer to percentiles.

z-scores calculation:

                    (70%)       z-score = (70 – 80)/5 = -2

This translates to percentile of 2.28%

                    (80%)       z-score = (80 – 80)/5 = 0

This translates to percentile of 50%.

Subtracting the percentiles will give us the final answer of 47.72%. 

5x + 5

step-by-step explanation:

you should always add the diagrams and graphs we cannot see. this particular question is kind of borderline because we can make a graph for you.

(f + g)x = -x^2 +3x + 5 + x^2 + 2x

(f + g)x = 5x + 5

the graph of z = 5x + 5 is shown below. always use desmos when in doubt.