may you can explain what step I may do. Thank you so much

7. According to news reports in early 1995, among the first Pentium chips Intel made, some had a peculiar defect, which rendered some rarely carriedout arithmetic operations incorrect. Any chip could therefore be classied into one of three categories: Good, broken (useless), or Defective (operable except for the peculiar defect described above). Suppose 70% 0f the chips made were good, 25% had the peculiar defect, and 5% were broken. If a random sample of 20 chips was selected, what is the probability that 15 were good, 3 defectives, and 2 broken