In a cross between two mice that are heterozygous for agouti, black, color, and piebaldism, what is the probability that offspring will have solid black fur along with large patches of white fur?

Because each gene segregates independently, you need to determine the probability of each genotype independently and then multiply the four probabilities together. The probability of offspring with solid color (aa) is 1/4; the probability of offspring with black fur (BBor Bb) is 3/4; the probability of colored fur (CC or Cc) is 3/4; and the probability of piebald, or white patches (pp), is 1/4. The combined probability is 1/4 x 3/4 x 3/4 x 1/4 = 9/256.