Normal distribution has a mean of 80 and a standard deviation of 10 9) The probability of a value between 75 and 90 equals:
A) 0.1498
B) 0.1915
C) 0.3413
D) 0.5328

the 3rd on is correct

step-by-step explanation:

if you was gonna solve for a, a is a   < -12

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15