how many 5 digit telephone numbers can be constructed using the digits 0 to 9if each number starts with 67 and no digit appears more than once?
plz give a solution

Question

how many 5 digit telephone numbers can be constructed using the digits 0 to 9if each number starts with 67 and no digit appears more than once?
plz give a solution

bahrom7893 · Answer

you have 5 digits:
_ _ _ _ _
the first two must be 67
67 _ _ _

anonymous · Answer

k

bahrom7893 · Answer

So now this means u have 1 option for the first number, 1 option for the 2nd number
1*1 _ _ _

bahrom7893 · Answer

Now for the 3rd number we have 8 options (because 6 and 7 were used up and no number can repeat)

anonymous · Answer

k

bahrom7893 · Answer

Following the same idea:
1*1*8*7*6 numbers can be constructed

anonymous · Answer

k i got it.thanx