3. -13 points DevoreStat9 2.E.034 My Notes Ask Your Teach Computer keyboard fail

Question

3. -13 points DevoreStat9 2.E.034 My Notes Ask Your Teach Computer keyboard failures can be attributed to electrical defects or mechanical defects. A repair facility currently has 25 failed keyboards, 12 of which have electrical defects and 13 of which have mechanical defects (a) How many ways are there to randomly select 6 of these keyboards for a thorough inspection (without regard to order)? ways (b) In how many ways can a sample of 6 keyboards be selected so that exactly two have an electrical defect? ways (c) If a sample of 6 keyboards is randomly selected, what is the probability that at least 5 of these will have a mechanical defect? (Round your answer to four decimal places.)

Explanation / Answer

Ans:

a)Number of ways to select 6 keyboards out of 25 keyboards

=25C6=(25*24*23*22*21*20)/(6*5*4*3*2*1)=177100 ways

b)Number of ways to select 6 keyboards so that exactly 2 electrical keyboards

=12C2*13C4

=66*715=47190 ways

c)Probability that atleast 5 will have mechanical defect=(13C5*12C1+13C6)/25C6

=(15444+1716)/177100

=17160/177100

=0.0969

Related Questions

Navigate

• Browse (All)
• Browse 3
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.