An analysis of the grades on the first test in history 101 revealed that they approximate a normal curve with a mean of 75 and a standard deviation of 8. the instructor wants to award the grade of a to the upper 10% of the test grades. to the nearest percent, what is the dividing point between an a and a b grade?
select one:
a. 80
b. 85
c. 90
d. 95

b. 85

Step-by-step explanation:

Average grade (μ) = 75

Standard deviation (σ) = 8

Assuming a normal distribution, the z-score corresponding to the upper 10% of the test grades is z = 1.28.

The minimum grade 'X' within the top 10% is given by:

Rounding to the nearest percent, the dividing point between an A and a B grade is 85.

answer set (b) 0.5, 3/4 80% is in order from least to greatest.  

step-by-step explanation:

in order to compare rational numbers to each other, it is much easier if they are in the same form.   typically, the best form in which to evaluate rational numbers is in decimals.   in order to convert a percent to a decimal, you would divide the given percentage by 100.   you can also accomplish the conversion by moving the decimal point over two places to the left.   for example, the decimal value of 80% is 80/100, or 0.8.   in order to convert a fraction to a decimal, you need to divide the numerator by the denominator.   for example, 3/4 is 0.75.   so, for choice (b) 0.5 3/4 (0.75), 80% (0.8) is the only choice in which the numbers are in order from least to greatest.  

18.75 gallons

step-by-step explanation: