The equation of the parabola whose focus is at (0, 5) and directrix at y = -5 is:

y = (1/20)x²
y = -(1/20)x²
x = (1/20)y²

How many real-number solutions does the equation have? -4x^2 + 10x + 6 = 0 a. no solutions b. two solutions c. infinitely many solutions d. one solution

Assume that females have pulse rates that are normally distributed with a mean of mu equals 72.0 beats per minute and a standard deviation of sigma equals 12.5 beats per minute. complete parts (a) through (c) below. a. if 1 adult female is randomly selected, find the probability that her pulse rate is between 65 beats per minute and 79 beats per minute. the probability is? b. if 16 adult females are randomly selected, find the probability that they have pulse rates with a mean between 65 beats per minute and 79 beats per minute. the probability is? c. why can the normal distribution be used in part (b), even though the sample size does not exceed 30?

While on a train trip, marsha noticed that there were 35 people in her train car. after the next stop, there were only 21 people in her car. if p represents the percent decrease in the number of people in marsha's train car, what is p?