Webwork Problems - 3.5 Bernoulli Trials

Find the probability of the event:
A die is rolled 18 times and two threes come up.

At least 3 Failures in 7 Trials with prob. of 0.6?

Assume that showing a car is a Bernoulli trial, and each time she shows a car, there is a probability of 0.05 that the customer will buy the car. The saleswoman has a goal of selling at least one car a week. How many cars must she show so that the probability of her reaching her goal is at least 0.74?

Assume that the fisherman can use between 4 and 7 lines. With 4 lines, the probability of a catch on each line is 0.71. With 5 this probability is 0.67, with 6 it is 0.51, and with 7 the probability is 0.4. How many lines should the fisherman use to maximize the probability of catching at least 2 fish?

Assume that n = 16, and p = [ 4/5]. Find the probability of at least 2 successes and at least 2 failures

Assume the box contains 7 balls:
3 red, 2 blue, and 2 yellow.
A ball is drawn and its color noted. If the ball is yellow, it is replaced; otherwise, it is not. A second ball is then drawn and its color is noted.
What is the probability that the first ball was yellow, given that the second was red?