Erica walked down a trail into a valley. v(d) models erica's vertical distance from the top of the valley (in kilometers) after walking d kilometers along the trail. what does the statement v(2)= t mean?

a= erica's vertical distance from the top of the valley was the same after she had walked 2 km and after she had walked t kilometers.
b= after she had walked 2 km along the trail, erica's vertical distance from the top of the valley was equal to t kilometers.
c= after she had walked t kilometers along the trail, erica's vertical distance from the top of the valley was equal to 2 km

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?