are repeated? 4. Suppose you are interested in obtaining a MI 10-digit phone num

Question

are repeated? 4. Suppose you are interested in obtaining a MI 10-digit phone number. S digit area code, a 3-digit prefix, and a 4-digit ending. uch phone numbers have a 3- According to Wikipedia there are 12 different area codes in MI. Furthermore, prefixes cannot begin with a 0 or a 1. How many possible phone numbers can be created? a) How many phone numbers have a 616 area code, a prefix where all three digits are identical (but not a 0 or a l), and an ending where none of the digits are identical? b)

Explanation / Answer

4a) here for there are 12 area code ; for first digit of prefix 8 choice and for rest 10 choices ; for 4 ending digits 10 choices for each ; hence total phone numbers =12*8*10*10*10*10*10*10

=96000000

b)

here as area code is fixed therefore one choice for it ; for prefix 8 choice as 0,1 not allowed and all are same ; for ending digit 10; second 9; third 8 and for fourth 7 choices are there

total choices =1*8*10*9*8*7=40320

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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